Co-reporter:Wan-Fu Ma, Cheng Zhang, Yu-Ting Zhang, Meng Yu, Jia Guo, Ying Zhang, Hao-Jie Lu, and Chang-Chun Wang
Langmuir June 10, 2014 Volume 30(Issue 22) pp:6602-6611
Publication Date(Web):June 10, 2014
DOI:10.1021/la501381v
Magnetic yolk–shell MSP@ZrO2 microspheres consisting of a movable magnetic supraparticle (MSP) core and a crystalline ZrO2 shell were synthesized via a two-step controlled “sol–gel” approach for the first time. First, a large amount of the generated hydrolyzate Zr(OH)4 was firmly fixed onto the surface of the cross-linked polymethylacrylic acid matrix via a strong hydrogen-bonding interaction between Zr(OH)4 and the carboxyl groups. Then a calcination process was adopted to convert the Zr(OH)4 into a continuous ZrO2 shell and simultaneously make the ZrO2 shell crystallized. At the same time, the polymer matrix could be selectively removed to form a yolk–shell structure, which has better dispersibility and higher adsorbing efficiency of phosphopeptides than its solid counterpart. The formation mechanism of such yolk–shell microspheres could be reasonably proved by the results of TEM, TGA, VSM, XRD, and FT-IR characterization. By taking advantage of the unique properties, the yolk–shell MSP@ZrO2 exhibited high specificity and great capability in selective enrichment of phosphopeptides, and a total of 33 unique phosphopeptides mapped to 33 different phosphoproteins had been identified from 1 mL of human saliva. This result clearly demonstrated that the yolk–shell MSP@ZrO2 has great performance in purifying and identifying the low-abundant phosphopeptides from real complex biological samples. Moreover, the synthetic method can be used to produce hybrid yolk–shell MSP@ZrO2–TiO2.
Co-reporter:Lijun You, Ruimin Li, Xu Dong, Fang Wang, Jia Guo, Changchun Wang
Journal of Colloid and Interface Science 2017 Volume 488() pp:109-117
Publication Date(Web):15 February 2017
DOI:10.1016/j.jcis.2016.10.086
A new type of optical probes, featuring surface enhanced Raman scattering (SERS) and fluorescence spectra dual-mode encoding, has been reported in this article. Based on the uniform micrometer-sized melamine resin/Ag nanoparticles (MRM/Ag-NPs) composite microspheres, the SERS reporters and fluorescent probes were successfully fixed onto the different layers of the MEM/Ag-NPs microspheres, which supported the sensitive DNA detecton. The two spectroscopic methods commonly considered to be contradictive to each other, yet the optical signals were separable in the experiments. The dual-encoding strategy and single microsphere detecton method put the number of available independent codes to be rough the multiple of those available in the two optical detection channels, which increases far more rapidly than the summation of the two channels. As a proof of cencept, the utility of this dual spectrum mode SERS-fluoresecence encoded microsphere (SFEM) was demonstrated in a specific DNA detection using complimentary ssDNA functionalized magnetic beads as the DNA capturing and separation agents. Excellent encoding results were demonstrated from the decoding of the SERS and fluorescence signals of the SFEM. The method appears to be general in scope and we expect that the SERS-fluoresecence encoded microspheres system is applicable to multiplex bioassays of a variety of biomolecules.A dual-mode spectroscopic encoded microspheres system based on the combination of fluorescence and SERS spectra encoding was designed and applied for specific DNA detection, which appears to be general in scope for multiplex bioassays of a variety of biomolecules.
Co-reporter:Dian Li;Luyan Sun;Yuting Zhang;Meng Yu;Jia Guo;Changchun Wang
Materials Chemistry Frontiers 2017 vol. 1(Issue 3) pp:521-529
Publication Date(Web):2017/03/09
DOI:10.1039/C6QM00049E
Efficient delivery of anticancer drugs to increase the intracellular drug concentration in targeted tissues is urgently needed in cancer chemotherapy, since clinical drugs usually have serious side effects on normal tissues. In this paper, we developed a new method to fabricate multi-functional porous magnetic nano-cargos by grafting PEG/folate onto the surface and storing doxorubicin in the pores of magnetic supraparticles for accurate delivery of anticancer drugs. The anticancer drug doxorubicin was fixed into the porous magnetic cores with acid-sensitive linkers, which can be broken in acidic intracellular environments or organelles; the superficial PEG chains on the magnetic cores not only enhanced the dispersion stability of the nano-cargos but also immobilized folate modified α-cyclodextrin by inclusion complexation, and the α-cyclodextrin derivatives could be flexibly replaced as needed. Remarkable proliferation inhibition of cancer cells and minor side effects on normal cells were achieved due to the controlled drug release manner of the nano-drug system, indicating that this kind of nano-cargo has great potential in cancer chemotherapy for personalized and accurate treatment.
Co-reporter:Zihao Zhang;Yongjing Li;Jiaxun Wan;Peihua Long;Jia Guo;Guosong Chen;Changchun Wang
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 15) pp:2410-2422
Publication Date(Web):2017/04/11
DOI:10.1039/C6PY02148D
Cisplatin is a widely-used chemotherapeutic drug in the clinic against a range of cancers. However, its anti-cancer efficacy and bioavailability are severely affected by systemic toxicity as well as drug resistance, which are mainly due to indiscriminate body distribution, low tumor accumulation and glutathione (GSH)-related drug detoxification. In this study, we prepared for the first time a new kind of Pt(IV)-crosslinked polymer nanoparticle with small, uniform size and high loading of cisplatin (60.8%). Such a kind of polymer nanodrug could keep its structural integrity during blood circulation to afford higher tumor accumulation via the EPR effect and receptor-mediated targeting effect, yet rapidly self-disintegrate to release drugs in response to tumor intracellular bio-reducing molecules, such as glutathione (GSH), resulting in efficient cancer cell inhibition and reduced systemic toxicity in vivo. Meanwhile, some of the cellular GSH molecules are depleted and transformed into an oxidized GSSG form to decrease their chelating interaction with platinum drugs, which attenuate their detoxifying effect on the Pt(II) species and may have an advantage for overcoming the tumor resistance to cisplatin induced by GSH. Moreover, the maximum tolerated dose of drug could be greatly enhanced (>3 fold), which improved the bioavailability of the nanodrug at relatively high doses. The present work provides a novel drug self-crosslinked design tactic and might open a new window for clinical cancer treatment.
Co-reporter:Zihao Zhang, Jiaxun Wan, Luyan Sun, Yongjing Li, Jia Guo, Changchun Wang
Journal of Controlled Release 2016 Volume 225() pp:96-108
Publication Date(Web):10 March 2016
DOI:10.1016/j.jconrel.2016.01.035
Biodegradable materials used for drug delivery are of great demand due to their ability to degrade into low molecular weight species and further excrete from the body by metabolism. Herein, we report a new kind of zinc(II) crosslinked poly(methacrylic acid) nanohydrogels (ZCLNs) inspired by zinc finger proteins with dual stimuli-triggered degradation (glutathione and pH) for the first time. Compared with the disulfide bond crosslinked nanohydrogels, this new kind of ZCLNs is beneficial to the degradation of a wide range of cells, including normal cells. Ex vivo fluorescence images showed that the DOX-loaded folate-PEG conjugated zinc(II)-crosslinked polymeric nanohydrogels (FPZCLNs-15) preferentially accumulated in tumor tissue and the accumulation in normal tissues was much less compared with DOX-loaded PZCLNs-15 (non-targeted nanohydrogels) and free DOX, the FPZCLNs-15 (targeting system) delivered DOX to the tumor site with approximately 3.6- and 1.6-fold higher than free DOX and PZCLNs-15, respectively. Meanwhile, the PZCLNs-15 and FPZCLNs-15 reduced the concentration of DOX in the heart by 3.2- and 5.0-fold respectively, as compared to the free DOX. Moreover, a superior tumor growth inhibition and negligible damage to normal organs like the heart and kidney, which is reported to be vulnerable to DOX-associated side effects, are further demonstrated.A new kind of zinc(II) crosslinked poly(methacrylic acid) nanohydrogels (ZCLNs) inspired by zinc finger proteins with dual stimuli-triggered degradation has been prepared for high efficiency delivery of the anticancer drugs.
Co-reporter:Ruimin Li, Yuting Zhang, Jing Tan, Jiaxun Wan, Jia Guo, and Changchun Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 14) pp:9384
Publication Date(Web):March 24, 2016
DOI:10.1021/acsami.6b02359
Utilizing fluorescence reporters and SERS probes as the security labels, a series of dual-mode encoded magnetic composite microspheres with micrometer size was designed and prepared for anticounterfeiting applications. At first, the micro-meter-sized melamine formaldehyde microspheres with different fluorescence molecules (FMF) were prepared by precipitation polymerization, and then the magnetite composite microspheres (FMF/MNPs) were fabricated by direct immobilization of magnetic nanoparticles (MNPs) onto the surface of FMF microspheres. After deposition of Ag nanoparticles (Ag-NPs) onto FMF/MNPs microspheres, the SERS probes were absorbed onto the surface of Ag-NPs, and then a protection layer of silica was coated on the composite microspheres by Stöber method. The combination of different fluorescence reporters and SERS probes greatly increased the encoding complexity and volume for high-level anticounterfeiting. The structure of the dual-encoded FMF/MNPs/Ag-NPs/SiO2 composite microspheres was characterized by FESEM, TEM, FLS(fluorescence spectrometer), XRD, VSM, UV–vis and EDS. The embedded magnetic nanoparticles enable the composite microspheres to be quickly isolated from the marked latex paint by magnet at the concentration of as low as 1 ppm, and the covert tag information can be read out even from one composite microsphere. In addition, the covert security information in the marked coating film can be also read out in situ and the existence of the composite microspheres does not influence the visible appearance of the coating film. All the above outstanding properties will make these dual-mode encoded composite microspheres as advanced security tags for next-generation anticounterfeiting applications.Keywords: anticounterfeiting; dual-encoded; fingerprint characteristics; fluorescence reporters; Raman probes; SERS
Co-reporter:Ranjan K. Kamat, Yuting Zhang, Murali Anuganti, Wanfu Ma, Iman Noshadi, Hailin Fu, Stephen Ekatan, Richard Parnas, Changchun Wang, Challa V. Kumar, and Yao Lin
Langmuir 2016 Volume 32(Issue 44) pp:11573-11579
Publication Date(Web):October 24, 2016
DOI:10.1021/acs.langmuir.6b02573
Polycatalytic enzyme complexes made by immobilization of industrial enzymes on polymer- or nanoparticle-based scaffolds are technologically attractive due to their recyclability and their improved substrate binding and catalytic activities. Herein, we report the synthesis of polycatalytic complexes by the immobilization of nonprocessive cellulases on the surface of colloidal polymers with a magnetic nanoparticle core and the study of their binding and catalytic activities. These polycatalytic cellulase complexes have increased binding affinity for the substrate. But due to their larger size, these complexes were unable to access to the internal surfaces of cellulose and have significantly lower binding capacity when compared to those of the corresponding free enzymes. Analysis of released soluble sugars indicated that the formation of complexes may promote the prospect of having consistent, multiple attacks on cellulose substrate. Once bound to the substrate, polycatalytic complexes tend to remain on the surface with very limited mobility due to their strong, multivalent binding to cellulose. Hence, the overall performance of polycatalytic complexes is limited by its substrate accessibility as well as mobility on the substrate surface.
Co-reporter:Hai-Qiu Wu and Chang-Chun Wang
Langmuir 2016 Volume 32(Issue 25) pp:6211-6225
Publication Date(Web):June 2, 2016
DOI:10.1021/acs.langmuir.6b00842
Nanogels (or nanohydrogels) have been extensively investigated as one of the most promising nanoparticulate biomedical platforms owing to their advantageous properties that combine the characteristics of hydrogel systems with nanoparticles. Among them, smart nanogels that have the ability to respond to external stimuli, such as pH, redox, temperature, enzymes, light, magnetic field and so forth, are most attractive in the area of drug delivery. Besides, numerous multifunctionalized nanogels with high sensitivity and specificity were designed for diagnostic applications. In this feature article, we have reviewed and discussed the recent progress of biodegradable nanogels as smart nanocarriers of anticancer drugs and biomedical diagnostic agents for cancer.
Co-reporter:Sha Jin, Jiaxun Wan, Lizheng Meng, Xiaoxing Huang, Jia Guo, Li Liu, and Changchun Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 35) pp:19843
Publication Date(Web):August 19, 2015
DOI:10.1021/acsami.5b05984
The application of nanomaterials in intelligent drug delivery is developing rapidly for treatment of cancers. In this paper, we fabricated a new kind of protease/redox/pH stimuli-responsive biodegradable nanohydrogels with methacrylic acid (MAA) as the monomer and N,N-bis(acryloyl)cystamine (BACy) as the cross-linker through a facile reflux-precipitation polymerization. After that, the polyethylene glycol (PEG) and folic acid (FA) were covalently grafted onto the surface of the nanohydrogels for enhancement of their long in vivo circulation lifetime and active targeting ability to the tumor cells and tissues. This kind of nanohydrogels could be disassembled into short polymer chains (Mn < 1140; PDI < 1.35) both in response to glutathione (GSH) through reduction of the sensitive disulfide bonds and protease by breakage of the amido bonds in the cross-linked networks. The nanohydrogels were utilized to simultaneously load both hydrophilic drug doxorubicin (DOX) and hydrophobic drug paclitaxel (PTX) with high drug loading efficiency. The cumulative release profile showed that the drug release from the drug-loaded nanohydrogels was significantly expedited by weak acidic (pH 5.0) and reducing environment (GSH), which exhibited an distinct redox/pH dual stimuli-responsive drug release to reduce the leakage of drugs before they reach tumor site. In addition, the in vitro experiment results indicated that the multidrug-loaded system had synergistic effect on cancer therapy. Meanwhile, the acute toxicity and intravital fluorescence imaging studies were adopted to evaluate the biocompatibility and biotoxicity of the nanohydrogels, the experimental results showed that the PEG modification could greatly enhance the long in vivo circulation lifetime and reduce the acute toxicity (LD50: from 138.4 mg/kg to 499.7 mg/kg) of the nanohydrogels.Keywords: acute toxicity; biodegradable; dual-drug loading; intravital fluorescence imaging; multi stimuli-responsive; nanohydrogels; surface modification
Co-reporter:Ying Zhang, Meng Yu, Cheng Zhang, Yali Wang, Yi Di, Changchun Wang and Haojie Lu
Chemical Communications 2015 vol. 51(Issue 27) pp:5982-5985
Publication Date(Web):13 Feb 2015
DOI:10.1039/C4CC10285A
A novel method based on the conjunction of aldehydes from oxidized glycopeptides to aniline groups on magnetic nanoparticles via nonreductive amination is reported for the highly selective enrichment of N-glycopeptides. For the first time, a nonreductive amination reaction has been introduced into N-glycoproteome extraction, and correspondingly a new type of aniline-functionalized nanoparticle has been designed and synthesized.
Co-reporter:Dian Li, Yuting Zhang, Meng Yu, Qiao An, Jia Guo, Jennifer Q. Lu and Changchun Wang
Chemical Communications 2015 vol. 51(Issue 10) pp:1908-1910
Publication Date(Web):11 Dec 2014
DOI:10.1039/C4CC07985J
Porous magnetic supraparticles (p-MSPs) with surface area up to 285.4 m2 g−1 have been fabricated by a one-step etching method, which is 4 times greater than the unetched counterpart. They exhibit significantly better biodegradability than their counterpart in both mimicked physiological buffer solution and the cellular environment of HeLa cells.
Co-reporter:Sha Jin, Dian Li, Peng Yang, Jia Guo, Jennifer Q. Lu, Changchun Wang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2015 Volume 484() pp:47-55
Publication Date(Web):5 November 2015
DOI:10.1016/j.colsurfa.2015.07.041
•A new kind of redox/pH dual stimuli-responsive biodegradable PEGlated nanohydrogels.•The PEGlated nanohydrogels could be degraded into short linear polymer chains in tumor cells.•The hydrophilic nanohydrogels could simultaneously load hydrophilic drug doxorubicin (DOX) and hydrophobic drug paclitaxel (PTX).•This novel multi-drug-loaded system had synergistic effect on cancer therapy.Stimuli responsive drug delivery systems have attracted considerable attention due to their ability to deliver drugs on demand to special tissues and cells (e.g. cancer cells). In this paper, we fabricated a new kind of redox/pH dual stimuli-responsive biodegradable poly(methacrylic acid) (MAA) nanohydrogels crosslinked by N,N-bis(acryloyl)cystamine (BACy) through a facile reflux-precipitation polymerization. Subsequently polyethylene glycol (PEG) was grafted onto the surface of nanohydrogels to improve their long circulation time. This kind of PEGylated nanohydrogels could be degraded into short linear polymer chains in the solution of 10 mM glutathione (GSH) due to the sensitive disulfide bonds in the cross-linked networks. Interestingly, we found that the hydrophilic PEGylated nanohydrogels could be simultaneously loaded with hydrophilic drug doxorubicin (DOX) and hydrophobic drug paclitaxel (PTX) with high drug loading efficiency because of its regional hydrophobic nature in the nanohydrogels. The cumulative release profile showed that either lower pH (5.0) or reducing environment (GSH) or a combination could significantly accelerate the drug release from the drug-loaded nanohydrogels. In addition, the experimental results on living cells indicated that the multi-drug-loaded system had synergistic effect on cancer therapy.
Co-reporter:Peng Yang, Fangyuan Zhao, Jing Ding, Jia Guo, Weibin Shi, Changchun Wang, and Xinhua Hu
Chemistry of Materials 2014 Volume 26(Issue 6) pp:2121
Publication Date(Web):February 21, 2014
DOI:10.1021/cm4041924
We design and synthesize monodisperse multi-layer microbubbles (MLBs) with bubble-in-bubble structure using the polymer-backbone-transition method (PBTM). Besides the tunable layer number and microbubble size, we can accurately control the layer-to-layer space and the thickness of each layer. In comparison to traditional single-layer microbubbles, the MLBs can be used as a novel promising model of contrast agent for high-performance ultrasound imaging. The ultrasound signal of MLBs shows a strong structure coupling effect; as the number of layer increases, both the backscatter signal and lifespan increase significantly. We apply a classical acoustic theory to calculate the ultrasound scattering cross-section for the bubbles. It is found that the MLBs exhibit a larger ultrasound scattering cross-section than single-layer bubbles with the same size under certain experimental conditions. Such theoretical results agree well with the ultrasound experimental results.
Co-reporter:Dian Li, Yuting Zhang, Sha Jin, Jia Guo, Haifeng Gao and Changchun Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 32) pp:5187-5194
Publication Date(Web):12 Jun 2014
DOI:10.1039/C4TB00756E
Intelligent nanomaterials that are able to respond to environmental stimuli for sequential release of multiple payloads are highly desirable in applications of drug delivery systems. In this study, a core/shell-structured nanocarrier with an acid-dissolvable magnetic supraparticle (MSP) as core and a redox-degradable poly(methylacrylic acid-co-N,N-bis(acryloyl)cystamine) (P(MAA-Cy)) as shell was prepared using the distillation-precipitation polymerization technique, in which the magnetic core and the polymer shell were loaded with different guest molecules. Under physiological conditions similar to the cytoplasm of tumour cells, this MSP@P(MAA-Cy) microsphere showed a sequential degradation profile of the shell and the core. With dyes of fluorescein isothiocyanate (FITC) loaded in the core and rhodamine in the shell, the produced MSP-FITC@P(MAA-Cy)-Rho microspheres were applied in HeLa cell and HEK 293T cell cultures, showing selective degradation of the microspheres in HeLa cells to release the rhodamine and FITC dyes in sequence. When two anticancer drugs, i.e., paclitaxel (TXL) and doxorubicin (DOX), were loaded separately into the core and the shell domains of the microspheres, the experimental results showed that the MSP-TXL@P(MAA-Cy)-DOX nanodrug exhibited better inhibitive efficacy than the free drugs under the same dosing level, demonstrating the great potential of this stimuli-sensitive drug delivery system for programmed and stimuli-responsive drug release characteristics.
Co-reporter:Fang Wang, Yuting Zhang, Peng Yang, Sha Jin, Meng Yu, Jia Guo and Changchun Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 17) pp:2575-2582
Publication Date(Web):11 Dec 2013
DOI:10.1039/C3TB21359E
Functional polymeric microgels have great potential for biomedical applications owing to the outstanding advantages of their well-defined structures and tunable surface properties. However, traditional polymerization methods lack the efficient techniques needed for the fabrication of polymeric microgels. Herein, we have developed a novel technique, reflux-precipitation polymerization, for the preparation of a new type of monodisperse poly(ethylene glycol methacrylate phosphate) (PEGMP) microgel with a well-defined spherical structure and abundant phosphate groups. Furthermore, we have extended this technique to fabricate various monodisperse microgels baring different functional groups, including crosslinked PVIM, PHEMA and PVPBA microgels, as well as non-crosslinked poly(AAm-co-MAA) nanohydrogels, which could serve as promising candidates for specific protein enrichment and drug delivery systems. The morphologies and particle size distributions of the microgels were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), whereas the surface properties were measured via a zeta potential test. In addition, the use of the PEGMP microgels for the identification of phosphoproteins in both a protein mixture and drinking milk was investigated, and demonstrated high selectivity towards phosphoproteins.
Co-reporter:Yuting Zhang, Dian Li, Meng Yu, Wanfu Ma, Jia Guo, and Changchun Wang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 11) pp:8836
Publication Date(Web):April 25, 2014
DOI:10.1021/am501626t
Integration of the advantages of immobilized metal-ion affinity chromatography (IMAC) and magnetic microspheres is considered as an ideal pathway for quick and convenient separation of his-tagged proteins, but rare reports concern the natural histidine-rich proteins. In this article, a novel route was presented to fabricate magnetic microspheres composed of a high-magnetic-response magnetic supraparticle (Fe3O4) core and a Ni2+-immobilized cross-linked polyvinyl imidazole (PVIM) shell via reflux-precipitation polymerization. The unique as-prepared Fe3O4/PVIM-Ni2+ microspheres possessed uniform flower-like structure, high magnetic responsiveness, abundant binding sites, and very easy synthesis process. Taking advantage of the pure PVIM-Ni2+ interface and high Ni2+ loading amount, the microspheres exhibited remarkable selectivity, excellent sensitivity, large enrichment capacity, and high recyclability in immobilization and separation of his-tagged recombinant proteins. More interestingly, it was found that the Fe3O4/PVIM-Ni2+ microspheres also showed excellent performance for removal of the natural histidine-rich bovine serum albumin (BSA) from the complex real sample of fetal bovine serum due to the exposed histidine residues. Considering their multiple merits, this new type of Fe3O4/PVIM-Ni2+ nanomaterial displays great potential in enriching low-abundant his-tagged proteins or removing high-abundant histidine-rich natural proteins for proteomic analysis.Keywords: affinity ligand; BSA; Fe3O4/PVIM-Ni2+ core/shell microspheres; histidine-rich protein; removal; selective enrichment;
Co-reporter:Liting Liu, Meng Yu, Ying Zhang, Changchun Wang, and Haojie Lu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 10) pp:7823
Publication Date(Web):April 15, 2014
DOI:10.1021/am501110e
In view of the biological significance of glycosylation for human health, profiling of glycoproteome from complex biological samples is highly inclined toward the discovery of disease biomarkers and clinical diagnosis. Nevertheless, because of the existence of glycopeptides at relatively low abundances compared with nonglycosylated peptides and glycan microheterogeneity, glycopeptides need to be highly selectively enriched from complex biological samples for mass spectrometry analysis. Herein, a new type of hydrazide functionalized core–shell magnetic nanocomposite has been synthesized for highly specific enrichment of N-glycopeptides. The nanocomposites with both the magnetic core and the polymer shell hanging high density of hydrazide groups were prepared by first functionalization of the magnetic core with polymethacrylic acid by reflux precipitation polymerization to obtain the Fe3O4@poly(methacrylic acid) (Fe3O4@PMAA) and then modification of the surface of Fe3O4@PMAA with adipic acid dihydrazide (ADH) to obtain Fe3O4@poly(methacrylic hydrazide) (Fe3O4@PMAH). The abundant hydrazide groups toward highly specific enrichment of glycopeptides and the magnetic core make it suitable for large-scale, high-throughput, and automated sample processing. In addition, the hydrophilic polymer surface can provide low nonspecific adsorption of other peptides. Compared to commercially available hydrazide resin, Fe3O4@PMAH improved more than 5 times the signal-to-noise ratio of standard glycopeptides. Finally, this nanocomposite was applied in the profiling of N-glycoproteome from the colorectal cancer patient serum. In total, 175 unique glycopeptides and 181 glycosylation sites corresponding to 63 unique glycoproteins were identified in three repeated experiments, with the specificities of the enriched glycopeptides and corresponding glycoproteins of 69.6% and 80.9%, respectively. Because of all these attractive features, we believe that this novel hydrazide functionalized core–shell magnetic nanocomposite will shed new light on the profiling of N-glycoproteome from complex biological samples in high throughput.Keywords: enrichment; glycopeptide; hydrazide chemistry; mass spectrometry; nanocomposite;
Co-reporter:Ying Zhang, Wanfu Ma, Cheng Zhang, Changchun Wang, and Haojie Lu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 9) pp:6290
Publication Date(Web):April 18, 2014
DOI:10.1021/am501339e
The efficient isolation of low-abundance phosphopeptides from complicated biological samples containing a significant quantity of nonphosphopeptides and proteins is essential for phosphopeptidome research but remains a great challenge. In this Article, magnetic composite microspheres comprising a magnetic colloidal nanocrystal cluster core and a mesoporous titania shell with an average pore diameter of 3.4 nm were modified by directly coating an amorphous titania shell onto the magnetite core, followed by converting the amorphous titania shell into a crystalline structure via a hydrothermal process at 80 °C. The as-prepared magnetic mesoporous titania microspheres possess a remarkable specific surface area that is as high as 603.5 m2/g, which is an appropriate pore size with a narrow size distribution and a high magnetic responsiveness. These outstanding features imply that the composite microspheres exhibit extraordinary performance in phosphopeptidome research, including high specificity toward phosphopeptides, an excellent size-exclusion effect against phosphoproteins, exceptional enrichment capacity, and efficient separation from mixtures. Encouraged by the experimental results, we employed this method to investigate the phosphopeptidome of snake venom for the first time. A total of 35 phosphopeptides was identified from the snake venom from the family Viperidae, accounting for 75% of the total identified peptides. This result represents the largest data set of the phosphopeptidome in snake venom from the family Viperidae.Keywords: hydrothermal process; magnetic composite microspheres; mesoporous titania; phosphopeptidome; size-exclusion effect;
Co-reporter:Peng Yang, Fang Wang, Xianfu Luo, Yuting Zhang, Jia Guo, Weibin Shi, and Changchun Wang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 15) pp:12581
Publication Date(Web):July 15, 2014
DOI:10.1021/am502550b
Nanorattles, as promising functional hollow nanomaterials, show considerable advantages in a variety of applications for drug delivery, biosensors, and biomedical imaging because of their tailored ability in both the movable core and shell. In this study, we formulate a facile controllable route to synthesize a monodisperse magnetic nanorattle with an Fe3O4 superparticle as the core and poly(vinylsilane) (PVS) as the outer shell (Fe3O4@air@PVS) using the polymer-backbone-transition strategy. In the process of synthesis, besides acting as the precursor for the PVS shells of nanorattles, organosilica (o-SiO2) plays the role of template for the middle cavities. The structures of nanorattles can be easily formed via etching treatment of NaOH solution. Through encapsulating sensitive perfluorohexane (PFH) in the cavities of Fe3O4@air@PVS, the biocompatible magnetic nanosystem shows a relatively stable ultrasound signal intensity and a high r2 value of 62.19 mM–1 s–1 for magnetic resonance imaging (MRI). After intravenous administration of nanorattles to a healthy rat, dramatically positively enhanced ultrasound imaging and negatively enhanced T2-weighted MRI are detected in the liver. Furthermore, when the Fe3O4@PFH@PVS nanorattles are administered to tumor-bearing mice, a significant passive accumulation in the tumor via an electron paramagnetic resonance effect is detected by both ultrasound imaging and MRI. In vivo experiments indicate that the obtained Fe3O4@PFH@PVS nanorattles can be used as dual-modality contrast agents for simultaneous ultrasound and MRI detection.Keywords: contrast agent; iron oxide; MRI; nanorattle; ultrasound imaging
Co-reporter:Ying Zhang, Meng Yu, Cheng Zhang, Wanfu Ma, Yuting Zhang, Changchun Wang, and Haojie Lu
Analytical Chemistry 2014 Volume 86(Issue 15) pp:7920
Publication Date(Web):July 21, 2014
DOI:10.1021/ac5018666
For the highly efficient extraction of the N-glycoproteome, a novel solid-phase extraction method based on oxime click chemistry has been developed. With the use of a newly synthesized aminooxy-functionalized magnetic nanoparticle, the oxidized glycan chains on glycopeptides readily react with the aminooxy groups through oxime click chemistry, resulting in the highly selective extraction of glycopeptides. Compared to the traditional hydrazide chemistry-based method, which takes 12–16 h of coupling time, this new method renders excellent enrichment performance within 1 h. Furthermore, the enrichment sensitivity (fmol level), selectivity (extracting glycopeptides from mixtures of nonglycopeptides at a 1:100 molar ratio), and reproducibility (CVs < 20%) are also dramatically improved. We have successfully profiled the N-glycoproteome from only 1 μL of human colorectal cancer serum using this innovative protocol, which offers a more efficient alternative N-glycoproteome extraction method.
Co-reporter:Wanfu Ma, Yuting Zhang, Meng Yu, Jiaxun Wan and Changchun Wang
RSC Advances 2014 vol. 4(Issue 18) pp:9148-9151
Publication Date(Web):23 Jan 2014
DOI:10.1039/C3RA47038E
An ultrafast, green and efficient microwave-assisted hydrothermal crystallization method was developed to convert the amorphous titania shell of MSP@TiO2 to uniform mesoporous anatase structure for highly selective and effective enrichment of phosphopeptides.
Co-reporter:Wanfu Ma, Ying Zhang, Weili Miao, Cheng Zhang, Meng Yu, Yuting Zhang, Jia Guo, Haojie Lu and Changchun Wang
RSC Advances 2014 vol. 4(Issue 81) pp:42957-42964
Publication Date(Web):18 Aug 2014
DOI:10.1039/C4RA05822D
The selective extraction of phosphopeptidome from complicated biological samples is of great importance for the development of diagnostic and prognostic biomarkers, but still remains a challenge. In this work, rattle-type mTiO2@P(NIPAM-co-MBA) composite microspheres comprising a mesoporous crystalline mTiO2 core, an intermediate hollow space and a crosslinked P(NIPAM-co-MBA) network shell were elaborately designed and fabricated via two-step reflux-precipitation polymerization followed by a hydrothermal process. First, a non-crosslinked PMAA layer was directly coated onto the surface of the TiO2 core without any pretreatment. Then, the formed TiO2@PMAA was encapsulated with another crosslinked P(NIPAM-co-MBA) layer with the aid of the strong hydrogen-bonding interaction between the two polymer layers. Finally, a hydrothermal process was adopted to convert the TiO2 core into a crystalline and mesoporous counterpart. At the same time, a non-crosslinked PMAA layer was selectively removed to form a rattle-type structure. The crosslinked P(NIPAM-co-MBA) shell makes the rattle-type mTiO2@P(NIPAM-co-MBA) possess great size-exclusion effect against both high-molecular-weight nonphosphoproteins and high-molecular-weight phosphoproteins, while the mTiO2 core was responsible of the selective enrichment of the low-molecular-weight phosphopeptides. With the help of these unique properties, the rattle-type mTiO2@P(NIPAM-co-MBA) microspheres show excellent potential for the one-step selective extraction of the phosphopeptidome.
Co-reporter:Peng Yang, Dian Li, Sha Jin, Jing Ding, Jia Guo, Weibin Shi, Changchun Wang
Biomaterials 2014 35(6) pp: 2079-2088
Publication Date(Web):
DOI:10.1016/j.biomaterials.2013.11.057
Co-reporter:Wan-Fu Ma, Cheng Zhang, Yu-Ting Zhang, Meng Yu, Jia Guo, Ying Zhang, Hao-Jie Lu, and Chang-Chun Wang
Langmuir 2014 Volume 30(Issue 22) pp:6602-6611
Publication Date(Web):2017-2-22
DOI:10.1021/la501381v
Magnetic yolk–shell MSP@ZrO2 microspheres consisting of a movable magnetic supraparticle (MSP) core and a crystalline ZrO2 shell were synthesized via a two-step controlled “sol–gel” approach for the first time. First, a large amount of the generated hydrolyzate Zr(OH)4 was firmly fixed onto the surface of the cross-linked polymethylacrylic acid matrix via a strong hydrogen-bonding interaction between Zr(OH)4 and the carboxyl groups. Then a calcination process was adopted to convert the Zr(OH)4 into a continuous ZrO2 shell and simultaneously make the ZrO2 shell crystallized. At the same time, the polymer matrix could be selectively removed to form a yolk–shell structure, which has better dispersibility and higher adsorbing efficiency of phosphopeptides than its solid counterpart. The formation mechanism of such yolk–shell microspheres could be reasonably proved by the results of TEM, TGA, VSM, XRD, and FT-IR characterization. By taking advantage of the unique properties, the yolk–shell MSP@ZrO2 exhibited high specificity and great capability in selective enrichment of phosphopeptides, and a total of 33 unique phosphopeptides mapped to 33 different phosphoproteins had been identified from 1 mL of human saliva. This result clearly demonstrated that the yolk–shell MSP@ZrO2 has great performance in purifying and identifying the low-abundant phosphopeptides from real complex biological samples. Moreover, the synthetic method can be used to produce hybrid yolk–shell MSP@ZrO2–TiO2.
Co-reporter:Jia Guo;Wuli Yang ;Changchun Wang
Advanced Materials 2013 Volume 25( Issue 37) pp:5196-5214
Publication Date(Web):
DOI:10.1002/adma.201301896
Abstract
Magnetic nanoparticles (MNPs) bear many intriguing properties such as superparamagnetism, high specific surface area, remarkable colloidal stability and biocompatibility, which evoke great interest and desire of exploration in biomedical applications. For the use in the complicated physiological environment, MNPs are still being developed to have the enhanced performances and down-to-earth practicality. Engineering of MNPs into hierarchical structures is thus proposed to create a new family of magnetic materials, magnetic colloidal supraparticles (MCSPs), which exhibit collective properties and unique nanomaterial characters. From a biomedical point of view, applicability of MCSPs is somewhat more distinctive in contrast to their primary MNPs, because MCSPs are amenable to modulation of secondary structure, promotion of magnetic responsiveness and ease of function design. As a result, MCSPs have been subject to intense researches in recent years, with the aim to develop outstanding composite materials for biomedical applications. In this review, we embark on an overview of foundational topics that detail the design and fabrication of MCSPs by evaporation-induced emulsion and solvothermal techniques, and continue with a guideline for modification of MCSPs with inorganic oxides and organic polymers. Particular focus is then placed on the biomedical applications of modified MCSPs. Many examples illustrate the latest progress in design of MCSP-based microspheres for magnetic resonance imaging, targeted drug delivery, sensing, and harvesting of peptides/proteins. After these detailed accounts, the current challenges and future development of researches and applications are discussed as a conclusion to the review.
Co-reporter:Wanfu Ma;Ying Zhang;Lulu Li;Yuting Zhang;Meng Yu;Jia Guo;Haojie Lu;Changchun Wang
Advanced Functional Materials 2013 Volume 23( Issue 1) pp:107-115
Publication Date(Web):
DOI:10.1002/adfm.201201364
Abstract
Architectural design is essential to achieve ideal chemical and biological properties of nanomaterials. In this article, a novel route to fabricate high-quality magnetic composite microspheres composed of a high-magnetic-response magnetic colloid nanocrystal cluster (MCNC) core, a poly(methylacrylic acid) (PMAA) interim layer, and a Ti4+-immobilized poly(ethylene glycol methacrylate phosphate) (PEGMP) shell via two-step distillation–precipitation polymerization is presented. The unique as-synthesized MCNC@PMAA@PEGMP-Ti4+ composite microsphere is investigated for its applicability for selective enrichment of phosphopeptides from complex biological samples. The experiment results demonstrate that, by taking advantage of the pure phosphate–Ti4+ interface and high Ti4+ loading amount, the MCNC@PMAA@PEGMP-Ti4+ composite microsphere possesses remarkable selectivity for phosphopeptides even at a very low molar ratio of phosphopeptides/nonphosphopeptides (1:500). The extreme sensitivity, excellent recovery of phosphopeptides, and high magnetic susceptibility are also proven. These outstanding features demonstrate that the MCNC@PMAA@PEGMP-Ti4+ composite microspheres have great benefit for the pretreatment before mass spectrometric analysis of phosphopeptides. Furthermore, the performance of the approach in selective enrichment of phosphopeptides from drinking milk and human serum gives powerful evidence for its high selectivity and effectiveness in identifying the low-abundant phosphopeptides from complicated biological samples.
Co-reporter:Shuai Xu, Baoru Yin, Jia Guo and Changchun Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 33) pp:4079-4087
Publication Date(Web):03 Jun 2013
DOI:10.1039/C3TB20238K
Uniform hollow magnetic supraparticles (HMSPs) consisting of nanocrystal aggregates in shells are designed and fabricated via a one-pot microwave irradiation process within 10 min, employing casein, a major milk protein, as a structure-directing agent responsible for the formation of hollow structures. The casein micelle (CM)-mediated self-assembled HMSPs exhibit structural uniformity, excellent aqueous dispersibility, enhanced biocompatibility, as well as a high saturation magnetization (∼70 emu g−1). Herein, CMs serve as soft templates to induce inner hollow cavities through electrostatic interactions between negative CM “brushes” and positive Fe(III) species, and subsequent degradation of the inner cores under microwave irradiation, meanwhile improving the colloidal stability and biocompatibility of the HMSPs. Besides, the interior cavity size of the HMSPs could be readily tuned in the range of 40 nm to 150 nm, simply by varying the feeding dosage of casein. In light of the interior void and desirable physicochemical properties, the role of HMSPs serving as vehicles for the controlled delivery of DOX into cancer cells has been investigated. Drug release profiles are shown to be pH-responsive with up to 83% DOX release in acidic environments (pH 4.0 and 5.0), whereas low DOX (18%) release occurs at neutral pH (pH 7.4) within 48 h, indicating minimal premature drug release. Moreover, intracellular tracking experiments reveal that DOX-loaded HMSPs could efficiently be taken up by KB cells and exhibit potent anti-proliferation and inhibitory effects against KB cells, as compared to free DOX. Importantly, the DOX-loaded HMSPs show limited cytotoxicity against normal HEK 293 cells with 70% retained viability after incubation at a high concentration of 5.0 μg mL−1, which further demonstrated the potential of microwave-driven HMSPs as desirable drug delivery vehicles.
Co-reporter:Peng Yang, Jing Ding, Jia Guo, Weibin Shi, Jack J. Hu and Changchun Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 4) pp:544-551
Publication Date(Web):06 Nov 2012
DOI:10.1039/C2TB00059H
We present a novel self-templating strategy for directly fabricating monodisperse hollow polymer microspheres (HPMs) from vinyl-containing organosilica microspheres (VOMs) through a polymer-backbone-transition method (PBTM). The VOMs play the roles of both templates and precursors in the new shells. The uniform HPMs with varying sizes from 320 nm to 1.6 μm could be obtained by controlling the diameter of the VOMs. Depending on the progress of outer-to-inner shell formation, the range of shell thickness is broadly tunable from 15 nm to 290 nm. Theoretically, through introduction of a suitable vinyl monomer in the shell-formation step, a variety of double-shell hollow polymer microspheres (ds-HPMs) could be fabricated based on this strategy. We then synthesize ds-HPMs by copolymerization of VOMs with N-isopropyl acrylamide (NIPAM) in order to improve the dispersion stability of HPMs in water and provide better oscillation and compressibility. In vitro and in vivo experimental results showed that the ds-HPMs possessed excellent echoing characteristics which could be applied as ultrasound contrast agents for the real-time guidance during the surgical process.
Co-reporter:Yuting Zhang, Yongkun Yang, Wanfu Ma, Jia Guo, Yao Lin, and Changchun Wang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 7) pp:2626
Publication Date(Web):March 7, 2013
DOI:10.1021/am4006786
A facile approach has been developed to synthesize Fe3O4/PMG (poly (N,N′-methylenebisacrylamide-co-glycidyl methacrylate)) core/shell microspheres using distillation–precipitation polymerization. Treating PMG shell with iminodiacetic acid (IDA) and Ni2+ yields composite microspheres of Fe3O4/PMG/IDA–Ni2+. The Ni2+ ions loaded on the surface of microspheres provide abundant docking sites for immobilization of histidine-tagged proteins. The high saturation magnetization of Fe3O4/PMG (23 emu/g), determined by vibrating sample magnetometer (VSM), allows an easy separation of the microspheres from solution under an external magnetic field. The composite microspheres were used to purify two His-tagged cellulolytic enzymes (Cel48F and Cel9G) directly from crude cell lysates with high binding affinity, capacity, and specificity. The microspheres can be recycled for many times without significant loss of binding capacity to enzymes. The immobilized enzymes on the surface of microspheres well retain their biological activities in degradation of cellulose. These materials show great potential in the biomedical and biotechnological applications that require low-cost purification of recombinant proteins and instant enzyme immobilization at an industrial scale.Keywords: cellulase; cellulosome; enzyme immobilization; Fe3O4/PMG core/shell microspheres; His-tagged protein; purification;
Co-reporter:Yuting Zhang, Lulu Li, Wanfu Ma, Ying Zhang, Meng Yu, Jia Guo, Haojie Lu, and Changchun Wang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 3) pp:614
Publication Date(Web):January 7, 2013
DOI:10.1021/am3019806
Designed with a two-in-one strategy, the magnetic mesoporous γ-Fe2O3 nanocrystal clusters (m-γ-Fe2O3) have been successfully prepared for integrating the functions of effective enrichment and quick separation of phosphopeptides into a single architecture. First, the mesoporous Fe3O4 nanocrystal clusters (mFe3O4) were synthesized by solvothermal reaction and then were subjected to calcination in air to form m-γ-Fe2O3. The obtained m-γ-Fe2O3 have spherical morphology with uniform particle size of about 200 nm and mesoporous structure with the pore diameter of about 9.7 nm; the surface area is as large as 117.8 m2/g, and the pore volume is 0.34 cm3/g. The m-γ-Fe2O3 possessed very high magnetic responsiveness (Ms = 78.8 emu/g, magnetic separation time from solution is less than 5 s) and were used for the selective enrichment of phosphopeptides for the first time. The experimental results demonstrated that the m-γ-Fe2O3 possessed high selectivity for phosphopeptides at a low molar ratio of phosphopeptides/nonphosphopeptides (1:100), high sensitivity (the detection limit was at the fmol level), high enrichment recovery (as high as 89.4%), and excellent speed (the enrichment can be completed in 10 min). Moreover, this material is also quite effective for enrichment of phosphopeptides from the real sample (drinking milk), showing great potential in the practical application.Keywords: enrichment; magnetic separation; mesoporous γ-Fe2O3; nanocrystal clusters; phosphopeptides;
Co-reporter:Dian Li, Yuting Zhang, Peng Yang, Meng Yu, Jia Guo, Jennifer Q. Lu, and Changchun Wang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 23) pp:12329
Publication Date(Web):November 25, 2013
DOI:10.1021/am4043596
Mesoporous magnetic supraparticles (meso-MSPs) as multifunctional targeted drug carriers have attracted much attention, because of their easy magnetic-field manipulation and in situ sensing functionality. In this paper, a Fe3+-selective chemodosimeter fluorescent probe (FP-1) was synthesized and loaded inside of the meso-MSPs (meso-MSPs/probe); the meso-MSPs/probe nanocomposites were then used to monitor the degradation of meso-MSPs in cells. In our experiments, strong fluorescence intensity was observed in HeLa cells, because of their acidic intracellular environment, which can quickly degrade the meso-MSPs and then release Fe3+ ions in cells that, in turn, activate the fluorescence of FP-1. Meanwhile, a very weak fluorescence signal was detected in HEK 293T cells due to the relative neutral intracellular environment of HEK 293T cells, which prevented the Fe3+ ion from leaching out of meso-MSPs. Moreover, this degradation–luminescence relationship of the meso-MSPs/probe nanocomposites not only assisted us to understand the degradation status of meso-MSPs in cells, but also allowed us to recognize the peculiarity of different cells with various intracellular environments.Keywords: bio-degradation; drug carrier; Fe3+-sensitive fluorescent probe; in situ monitoring; magnetic supraparticles (MSPs);
Co-reporter:Yuan-Jia Pan, Dian Li, Sha Jin, Chuan Wei, Ke-Yi Wu, Jia Guo and Chang-Chun Wang
Polymer Chemistry 2013 vol. 4(Issue 12) pp:3545-3553
Publication Date(Web):27 Mar 2013
DOI:10.1039/C3PY00249G
Folate-conjugated poly(N-(2-hydroxypropyl)methacrylamide-co-methacrylic acid) nanohydrogels were facilely prepared via distillation–precipitation polymerization and subsequent folate modification. Due to the nanohydrogels being crosslinked with disulphide bonds, they could be easily degraded into short polymer chains in the presence of glutathione, which will be beneficial for easily discharging the nanohydrogels from the body. Doxorubicin (DOX), a clinical anti-cancer drug, was efficiently loaded in the nanohydrogels (up to 39.3 wt%) by the electrostatic interactions between the amine group in doxorubicin (DOX) and the carboxyl groups in the nanohydrogels at neutral conditions. The cumulative release profile of the DOX-loaded nanohydrogels showed a relatively low level of drug release (23 wt% in 48 h) at pH 7.4 and a quick release (over 95 wt% in 2 h) at pH 5.0 with reducing environment, exhibiting pH/redox dual-stimuli-responsive drug release. The dose-dependent cytotoxicity of the drug-loaded nanohydrogels was studied by the CCK-8 assay. The nanohydrogels possess many favourable merits of drug carriers, such as excellent biocompatibility, high drug loading capacity, minimal drug release under an extracellular condition, rapid drug release in response to the intracellular level of pH and reducing environment, and folate-mediated endocytosis, which endow them as great candidates for targeted delivery of anti-cancer drugs.
Co-reporter:Li-Jun You, Qiao An, Jia Guo, Jack J. Hu and Chang-Chun Wang
RSC Advances 2013 vol. 3(Issue 38) pp:17469-17476
Publication Date(Web):10 Jul 2013
DOI:10.1039/C3RA42260G
Uniform MF/Ag-NPs core–shell composite microspheres were fabricated as isolated SERS (surface-enhanced Raman scattering)-active substrates through coating of Ag nanoparticles (Ag-NPs) onto MF (melamine formaldehyde resin) microspheres. These composite microspheres can be imaged and individually manipulated under an optical microscope. Their SERS spectra can be taken at the focal point to ensure the best analysis result or to recognize the identity of the microsphere for flow cytometry. In this paper, the SERS activity of the composite microspheres was evaluated using 4-ABT, 4-CBT, and 4-DTNB as the Raman reporting molecules; the SERS data of tetramethylthiuram disulfide were also acquired on the isolated MF/Ag-NPs core–shell composite microsphere. Due to the significant electromagnetic coupling effect created by the Ag-NPs on the MF microsphere, the SERS detection limits for 4-ABT, 4-CBT, and 4-DTNB were as low as 10−9 mol L−1, 10−10 mol L−1, and 10−8 mol L−1, respectively. For the insecticide tetramethylthiuram disulfide, the detection limit was 10−9 mol L−1 using the isolated MF/Ag-NPs microsphere as the SERS substrate. The SERS signal intensity linearly depended upon the concentration of tetramethylthiuram disulfide, indicating that the MF/Ag-NPs core–shell composite microsphere can be used for quantitative analysis of this insecticide.
Co-reporter:Ju-Mei Li, Wan-Fu Ma, Li-Jun You, Jia Guo, Jun Hu, and Chang-Chun Wang
Langmuir 2013 Volume 29(Issue 20) pp:6147-6155
Publication Date(Web):April 23, 2013
DOI:10.1021/la4006828
A new approach for sensitive detection of a specific ssDNA (single-stranded DNA) sequence based on the surface enhanced Raman spectroscopy (SERS) liquid chip is demonstrated. In this method, the probe DNA (targeting to one part of target ssDNA) was attached to the nano-SERS-tags (poly(styrene-co-acrylic acid)/(silver nanoparticles)/silica composite nanospheres), and the capture DNA (targeting to the other part of target ssDNA) was attached to the Fe3O4/poly(acrylic acid) core/shell nanospheres. The nano-SERS-tags with probe DNA were first allowed to undergo hybridization with the target ssDNA in solution to achieve the best efficiency. Subsequently, the magnetic composite nanospheres with capture DNA were added as the capturing substrates of the target ssDNA combined with the nano-SERS-tags. Upon attraction with an external magnet, the nanospheres (including the nano-SERS-tags) were deposited together due to the hybridization, and the deposit sediment was then analyzed by SERS. Quantitative detection of target ssDNA was achieved based on the well-defined linear correlation between the SERS signal intensity and the target ssDNA quantity in the range of 10 nM to 10 pM, and the limit of detection was approximately 10 pM. Multiplexed detection of up to three different ssDNA targets in one sample was demonstrated using three different types of nano-SERS-tags under a single excitation laser. The experimental results indicated that the liquid-phase DNA sequencing method, thus named the SERS liquid chip (SLC) method, holds significant promises for specific detection of trace targets of organisms.
Co-reporter:Dian Li, Yu-Ting Zhang, Meng Yu, Jia Guo, Deeptangshu Chaudhary, Chang-Chun Wang
Biomaterials 2013 34(32) pp: 7913-7922
Publication Date(Web):
DOI:10.1016/j.biomaterials.2013.06.046
Co-reporter:Qiao An, Peng Zhang, Jun-Mei Li, Wan-Fu Ma, Jia Guo, Jun Hu and Chang-Chun Wang
Nanoscale 2012 vol. 4(Issue 16) pp:5210-5216
Publication Date(Web):14 Jun 2012
DOI:10.1039/C2NR31061A
Highly active surface-enhanced Raman scattering (SERS) substrates of Ag nanoparticle (Ag-NP) modified Fe3O4@carbon core–shell microspheres were synthesized and characterized. The carbon coated Fe3O4 microspheres were prepared via a one-pot solvothermal method and were served as the magnetic supporting substrates. The Ag-NPs were deposited by in situ reduction of AgNO3 with butylamine and the thickness of the Ag-NP layer was variable by controlling the AgNO3 concentrations. The structure and integrity of the Fe3O4@C@Ag composite microspheres were confirmed by TEM, XRD, VSM and UV-visible spectroscopy. In particular, the Ag-NP coated Fe3O4@carbon core–shell microspheres were shown to be highly active for SERS detections of pentachlorophenol (PCP), diethylhexyl phthalate (DEHP) and trinitrotoluene (TNT). These analytes are representatives of environmentally persistent organic pollutants with typically low SERS activities. The results suggested that the interactions between the carbon on the microsphere substrates and the aromatic cores of the target molecules contributed to the facile pre-concentration of the analytes near the Ag-NP surfaces.
Co-reporter:Wan-Fu Ma, Lu-Lu Li, Ying Zhang, Qiao An, Li-Jun You, Ju-Mei Li, Yu-Ting Zhang, Shuai Xu, Meng Yu, Jia Guo, Hao-Jie Lu and Chang-Chun Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 45) pp:23981-23988
Publication Date(Web):01 Oct 2012
DOI:10.1039/C2JM35196J
Selective enrichment of glycopeptides from complicated biological samples is essential for MS-based glycoproteomics, but still remains a great challenge. In this study, we report an unprecedented ligand-free strategy for the selective enrichment of glycopeptides by simply utilizing the multivalent interaction between glycopeptides and silver nanoparticles (Ag-NPs) coated magnetic nanoarchitectures. The composite microspheres were deliberately designed to be constructed with a high-magnetic-response magnetic colloid nanocrystal cluster (MCNC) core, a poly(methacrylic acid) (PMAA) interim layer and a Ag-NPs functional shell with high coverage. Taking advantage of the reversible interaction of glycans with Ag-NPs and the high magnetic susceptibility of the magnetite core, the MCNC@PMAA@Ag-NPs microspheres possess remarkable selectivity for glycopeptides even at a low molar ratio of glycopeptides/non-glycopeptides (1:100) with a very rapid enrichment speed (only 1 min needed) and a simple operation procedure using magnetic separation. Applying this approach, we identified 127 unique glycopeptides mapped to 51 different glycoproteins from only 1 μL rat serum samples. These results clearly demonstrated that the MCNC@PMAA@Ag-NPs have great potential for purifying and identifying the low-abundant glycopeptides in complex biological samples.
Co-reporter:Wan-Fu Ma, Ke-Yi Wu, Jing Tang, Dian Li, Chuan Wei, Jia Guo, Shi-Long Wang and Chang-Chun Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 30) pp:15206-15214
Publication Date(Web):07 Jun 2012
DOI:10.1039/C2JM31721D
A smart magnetic targeting drug carrier (MCNC/PAA) comprising an approximately 100 nm sized magnetic colloid nanocrystal cluster (MCNC) core and a pH-responsive cross-linked poly(acrylic acid) (PAA) shell is reported. The abundant carboxyl groups in the shell enable the resultant MCNC/PAA to easily load a large amount of doxorubicin (DOX) (up to 44.6%) via the strong interaction between the DOX and the carboxyl group in a neutral solution. Interestingly, a synergistic pH-responsive effect derived from the entrapped DOX and PAA network was found to effectively manipulate the drug releasing behavior at 37 °C. It was found that the premature release was highly restricted at a pH of 7.4, and upon reduction in pH from 7.4 to 5.0 or 4.0, a large amount of drug was rapidly released. Compared with the synthesized MCNC/PNIPAM, MCNC/PHEMA and MCNC/PDMAPMA nanocarriers, the MCNC/PAA was preferably suited to drug delivery. In addition, the composite nanocarriers could be tracked by magnetic resonance imaging (MRI). The cytotoxicity assay of MCNC/PAA to normal cells indicated that the composite nanospheres were biocompatible and suitable as drug carriers. Meanwhile, the DOX-loaded composite nanospheres had more potent cytotoxicity than free DOX to HeLa cells. These results clearly imply that the MCNC/PAA nanocarrier is a promising platform that can be applied to construct a smart drug delivery system with magnetic targeting and pH-stimulation, as well as tracking by MRI.
Co-reporter:Ju-Mei Li, Chuan Wei, Wan-Fu Ma, Qiao An, Jia Guo, Jun Hu and Chang-Chun Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 24) pp:12100-12106
Publication Date(Web):03 Apr 2012
DOI:10.1039/C2JM30702B
In this study, a class of surface enhanced Raman spectroscopy (SERS) encoded core–shell nanospheres was synthesized as nano-SERS-tags for detecting specific DNA targets based on the sandwich hybridization assays. These core–shell nanospheres were synthesized by first depositing a layer of Ag-NPs (nanoparticles) onto the poly(styrene-co-acrylic acid) core and then the formation of a layer of uniform silica as the outer shell. The Ag-NPs served as SERS substrates with Raman active molecular probes adsorbed onto the Ag-NPs as indicative SERS molecular barcodes, and the silica coating shell was used for protecting the Ag-NPs and the Raman molecules from the exterior chemical and biological interference. The silica surfaces of nano-SERS-tags were further conjugated with probe DNA (pDNA) (nano-SERS-probes). The detection of single-stranded oligonucleotide (ssDNA) targets was successfully accomplished using the nano-SERS-probes in a chip-based sandwich hybridization assay in a mixed ssDNA target solution. The as-prepared nano-SERS-probes exhibited high chemical stability during the laser SERS experiments and the results were reproducible after a long-term storage. At least four different tags (a four “color” system) were quantitatively differentiated when simultaneously applied in the assays, indicating an excellent multiplexing potential of the method. Therefore, the as-prepared nano-SERS-probes are suitable for high specific detection of biomolecules with high sensitivity and remarkable multiplexing capability associated with the SERS method.
Co-reporter:Shuai Xu, Xiaojie Song, Jia Guo, and Changchun Wang
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 9) pp:4764
Publication Date(Web):September 5, 2012
DOI:10.1021/am301129n
Raspberry-like colloidal polymer/magnetite/silica composite microspheres were rationally fabricated based on in situ growth or interfacial immobilization of magnetic nanoparticles (MNPs) onto the polymer matrices and the followed sol–gel coating process. Monodisperse cross-linked poly(styrene-co-glycidyl methacrylate) microspheres were first prepared by surfactant-free emulsion polymerization, followed by surface modification of carboxyl or amine moieties through thiol-epoxy click chemistry. Then the carboxyl-modified microspheres were in situ decorated with MNPs through solvothermal process or chemical coprecipitation reaction. In parallel, incorporation of MNPs onto polymer matrices was also realized by the interaction of amine-modified polymer microspheres with carboxyl-capped MNPs based on the electrostatic interaction. The two pathways for synthesis of the composite microspheres decorated with MNPs were systematically investigated. Furthermore, the composite microspheres were coated with a thin layer of silica through a sol–gel process. The thus-produced magnetic composite microspheres with desirable magnetization (∼23 emu/g) served as effective supports for high-payload plasmid DNA enrichment (∼17 μg per mg of microspheres), much better than that of the commercial-available sample of SM1–015B (∼12 μg per mg of SM1–015B), shedding lights on the potential advantages of the nanoplatforms for separation of bioactive entities.Keywords: colloidal polymer microspheres; interfacial immobilization; magnetic composite microspheres; plasmid DNA separation; sol−gel process;
Co-reporter:Shuai Xu, Zhimin Luo, Yujie Han, Jia Guo and Changchun Wang
RSC Advances 2012 vol. 2(Issue 7) pp:2739-2742
Publication Date(Web):27 Feb 2012
DOI:10.1039/C2RA01169G
A facile and green microwave route was developed to ultra-quickly synthesize magnetite colloidal nanocrystal clusters (MCNCs) by reducing iron(III) chloride with ethylene glycol within 10 min at 150 °C. The obtained uniform MCNCs exhibited excellent crystallinity, saturation magnetization and sustained aqueous stability upon addition of stabilizers.
Co-reporter:Chuan Wei;Keyi Wu;Jumei Li;Wanfu Ma;Jia Guo;Jun Hu;Changchun Wang
Macromolecular Chemistry and Physics 2012 Volume 213( Issue 5) pp:557-565
Publication Date(Web):
DOI:10.1002/macp.201100607
Abstract
Well-defined amphiphilic diblock copolymers of poly(N-(2-hydroxypropyl)methacrylamide)-block-poly(benzyl methacrylate) (PHPMA-b-PBnMA) are synthesized using reversible addition–fragmentation chain transfer polymerization. The terminal dithiobenzoate groups are converted into carboxylic acids. The copolymers self-assemble into micelles with a PBnMA core and PHPMA shell. Their mean size is <30 nm, and can be regulated by the length of the hydrophilic chain. The compatibility between the hydrophobic segment and the drug doxorubicin (DOX) affords more interaction of the cores with DOX. Fluorescence spectra are used to determine the critical micelle concentration of the folate-conjugated amphiphilic block copolymer. Dynamic light scattering measurements reveal the stability of the micelles with or without DOX. Drug release experiments show that the DOX-loaded micelles are stable under simulated circulation conditions and the DOX can be quickly released under acidic endosome pH.
Co-reporter:Dian Li;Jing Tang;Jia Guo; Shilong Wang;Deeptangshu Chaudhary; Changchun Wang
Chemistry - A European Journal 2012 Volume 18( Issue 51) pp:16517-16524
Publication Date(Web):
DOI:10.1002/chem.201202249
Abstract
The fabrication of hierarchical magnetic nanomaterials with well-defined structure, high magnetic response, excellent colloidal stability, and biocompatibility is highly sought after for drug-delivery systems. Herein, a new kind of hollow-core magnetic colloidal nanocrystal cluster (HMCNC) with porous shell and tunable hollow chamber is synthesized by a one-pot solvothermal process. Its novelty lies in the “tunability” of the hollow chamber and of the pore structure within the shell through controlled feeding of sodium citrate and water, respectively. Furthermore, by using the ligand-exchange method, folate-modified poly(acrylic acid) was immobilized on the surface of HMCNCs to create folate-targeted HMCNCs (folate-HMCNCs), which endowed them with excellent colloidal stability, pH sensitivity, and, more importantly, folate receptor-targeting ability. These assemblages exhibited excellent colloidal stability in plasma solution. Doxorubicin (DOX), as a model anticancer agent, was loaded within the hollow core of these folate-HMCNCs (folate-HMCNCs-DOX), and drug-release experiments proved that the folate-HMCNCs-DOX demonstrated pH-dependent release behavior. The folate-HMCNCs-DOX assemblages also exhibited higher potent cytotoxicity to HeLa cells than free doxorubicin. Moreover, folate-HMCNCs-DOX showed rapid cell uptake apart from the enhanced cytotoxicity to HeLa cells. Experimental results confirmed that the synthesized folate-HMCNCs are smart nanovehicles as a result of their improved folate receptor-targeting abilities and also because of their combined pH- and magnetic-stimuli response for applications in drug delivery.
Co-reporter:Wan-Fu Ma, Ying Zhang, Lu-Lu Li, Li-Jun You, Peng Zhang, Yu-Ting Zhang, Ju-Mei Li, Meng Yu, Jia Guo, Hao-Jie Lu, and Chang-Chun Wang
ACS Nano 2012 Volume 6(Issue 4) pp:3179
Publication Date(Web):March 27, 2012
DOI:10.1021/nn3009646
Selective enrichment of phosphoproteins or phosphopeptides from complex mixtures is essential for MS-based phosphoproteomics, but still remains a challenge. In this article, we described an unprecedented approach to synthesize magnetic mesoporous Fe3O4@mTiO2 microspheres with a well-defined core/shell structure, a pure and highly crystalline TiO2 layer, high specific surface area (167.1 m2/g), large pore volume (0.45 cm3/g), appropriate and tunable pore size (8.6–16.4 nm), and high magnetic susceptibility. We investigated the applicability of Fe3O4@mTiO2 microspheres in a study of the selective enrichment of phosphopeptides. The experiment results demonstrated that the Fe3O4@mTiO2 possessed remarkable selectivity for phosphopeptides even at a very low molar ratio of phosphopeptides/non-phosphopeptides (1:1000), large enrichment capacity (as high as 225 mg/g, over 10 times as that of the Fe3O4@TiO2 microspheres), extreme sensitivity (the detection limit was at the fmol level), excellent speed (the enrichment can be completed in less than 5 min), and high recovery of phosphopeptides (as high as 93%). In addition, the high magnetic susceptibility allowed convenient separation of the target peptides by magnetic separation. These outstanding features give the Fe3O4@mTiO2 composite microspheres high benefit for mass spectrometric analysis of phosphopeptides.Keywords: enrichment of phosphopeptides; magnetic clusters; mass spectrometric analysis; mesoporous microspheres; titanium oxide
Co-reporter:Feng Zhang;Guihua Hou;Shaojun Dai;Rong Lu;Changchun Wang
Colloid and Polymer Science 2012 Volume 290( Issue 13) pp:1341-1346
Publication Date(Web):2012 August
DOI:10.1007/s00396-012-2697-8
Thermosensitive PNIPAM microcontainers were prepared by using silica particles as template. Silica particles were prepared by the Stöber method and surface modified with linear P(NIPAM-co-MPS) chains. PNIPAM shell was then fabricated on the P(NIPAM-co-MPS)-modified silica particles through precipitation polymerization of NIPAM and MBA. Finally, PNIPAM microcontainers were obtained by removing the silica cores with NaOH. The materials were characterized by TEM, FTIR, GPC, and DLS. The PNIPAM microcontainers exhibit good thermosensitivity. The method to fabricate thermosensitive PNIPAM shell can be generalized to a versatile method for preparing PNIPAM shell on particles with silica surface, which includes surface modification with P(NIPAM-co-MPS) and precipitation polymerization of NIPAM and MBA using the modified particles as seed. Through this method, PNIPAM shell was successfully fabricated on iron oxide/silica nanostructures with a wormlike shape and relatively large size, which demonstrates the versatility of the method.
Co-reporter:Li-Jun You, Shuai Xu, Wan-Fu Ma, Dian Li, Yu-Ting Zhang, Jia Guo, Jack J. Hu, and Chang-Chun Wang
Langmuir 2012 Volume 28(Issue 28) pp:10565-10572
Publication Date(Web):June 19, 2012
DOI:10.1021/la3023562
An ultrafast, facile, and efficient microwave hydrothermal approach was designed to fabricate magnetic Fe3O4/phenol–formaldehyde (PF) core–shell microspheres for the first time. The structure of the Fe3O4/PF core–shell microspheres could be well controlled by the in situ polycondensation of phenol and formaldehyde with magnetic Fe3O4 clusters as the seeds in an aqueous solution without any surfactants. The effect of synthetic parameters, such as the feeding amounts of phenol, the dosages of formaldehyde, the reaction temperatures, and the microwave heating time, on the morphologies and sizes of the Fe3O4/PF microspheres were investigated in details. The phenol–formaldehyde shell is found to be evenly coated on Fe3O4 clusters within 10 min of the irradiation. The as-prepared microspheres were highly uniform in morphology, and the method was found to allow the shell thickness to be finely controlled in the range of 10–200 nm. The properties of the composite microspheres were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetic analysis (TGA), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The as-prepared Fe3O4/PF microspheres were monodisperse and highly dispersible in water, ethanol, N,N-dimethyformamide, and acetone, a beneficial quality for the further functionalization and applications of the Fe3O4/PF microspheres.
Co-reporter:Yuan-Jia Pan, Yuan-Yuan Chen, Dong-Rui Wang, Chuan Wei, Jia Guo, Da-Ru Lu, Chih-Chang Chu, Chang-Chun Wang
Biomaterials 2012 33(27) pp: 6570-6579
Publication Date(Web):
DOI:10.1016/j.biomaterials.2012.05.062
Co-reporter:Shuai Xu, Wan-Fu Ma, Li-Jun You, Ju-Mei Li, Jia Guo, Jack J. Hu, and Chang-Chun Wang
Langmuir 2012 Volume 28(Issue 6) pp:3271-3278
Publication Date(Web):January 30, 2012
DOI:10.1021/la2043137
An effective method was developed for synthesizing magnetite/polymer colloidal composite microspheres with controllable variations in size and shape of the nanostructures and desirable interfacial chemical functionalities, using surfactant-free seeded emulsion polymerization with magnetite (Fe3O4) colloidal nanocrystal clusters (CNCs) as the seed, styrene (St) as the monomer, and potassium persulfate (KPS) as the initiator. The sub-micrometer-sized citrate-acid-stabilized Fe3O4 CNCs were first obtained via ethylene glycol (EG)-mediated solvothermal synthesis, followed by 3-(trimethoxysilyl)propyl methacrylate (MPS) modification to immobilize the active vinyl groups onto the surfaces, and then the hydrophobic St monomers were polymerized at the interfaces to form the polymer shells by seeded emulsion radical polymerization. The morphology of the composite microspheres could be controlled from raspberry- and flower-like shapes, to eccentric structures by simply adjusting the feeding weight ratio of the seed to the monomer (Fe3O4/St) and varying the amount of cross-linker divinyl benzene (DVB). The morphological transition was rationalized by considering the viscosity of monomer-swollen polymer matrix and interfacial tension between the seeds and polymer matrix. Functional groups, such as carboxyl, hydroxyl, and epoxy, can be facilely introduced onto the composite microspheres through copolymerization of St with other functional monomers. The resultant microspheres displayed a high saturation magnetization (46 emu/g), well-defined core–shell nanostructures, and surface chemical functionalities, as well as a sustained colloidal stability, promising for further biomedical applications.
Co-reporter:Ju-Mei Li, Wan-Fu Ma, Chuan Wei, Jia Guo, Jun Hu and Chang-Chun Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 16) pp:5992-5998
Publication Date(Web):14 Mar 2011
DOI:10.1039/C0JM04343E
A new type of polymer core and silver nanoparticle/silica shell multifunctional composite microsphere is reported. The monodisperse polymer core of poly(styrene-co-acrylic acid), prepared by surfactant-free emulsion polymerization, serves as the supporting template to facilitate the synthesis and handling of the highly functionalized substrates to achieve consistent mechanical and surface chemical properties. The shell of silver nanoparticles, formed in situ by controlled interfacial reduction of AgNO3 with polyvinylpyrrolidone (PVP), serves as the optimal metal enhancer for surface enhanced Raman spectroscopy (SERS). The Ag nanoparticle shell is stabilized with a silica layer using a sol–gel process, which is also functionalizable with reactive epoxides for further bio-conjugation using epoxy ring-opening methods. Preliminary results indicated that the microspheres are easily prepared with exceptional chemical and physical uniformity. SERS experiments with 4-aminobenzenethiol (4-ABT) as the indicator showed that the resulting multifunctional microspheres allowed the production of highly consistent enhancement of the Raman signals down to nM concentrations of 4-ABT, making them highly desirable candidates as the enhancers for high performance SERS analysis and as SERS optical labels in biomedical imaging. The microspheres are robust and the high density of the SERS active Ag nanoparticles on the microspheres provided unique signal averaging for the method to be potentially quantitative which is an urgent goal for SERS substrate design and SERS analysis.
Co-reporter:Chuan Wei;Jia Guo ;Changchun Wang
Macromolecular Rapid Communications 2011 Volume 32( Issue 5) pp:451-455
Publication Date(Web):
DOI:10.1002/marc.201000708
Co-reporter:Zhe-Ying Shen, Long-Yu Li, Yat Li, Chang-Chun Wang
Journal of Colloid and Interface Science 2011 Volume 354(Issue 1) pp:196-201
Publication Date(Web):1 February 2011
DOI:10.1016/j.jcis.2010.10.023
The monodisperse hybrid silica particles (h-SiO2) were firstly prepared by a modified sol–gel process and the surface was modified in situ with double bonds, then abundant carboxyl moieties were introduced onto the surface of the silica core via thiol–ene click reaction. Afterward, the h-SiO2/TiO2 core/shell microspheres were prepared by hydrolysis of titanium tetrabutoxide (TBOT) via sol–gel process in mixed ethanol/acetonitrile solvent, in which the activity of TBOT could be easily controlled. The carboxyl groups on the surface of silica particles promote the formation of a dense and smooth titania layer under well control, and the layer thickness of titania could be tuned from 12 to 100 nm. The well-defined h-SiO2/TiO2 core/shell structures have been confirmed by electron microscopy and X-ray photoelectron spectroscopy studies. After calcination at 500 °C for 2 h, the amorphous TiO2 layer turned into anatase titania. These anatase titania-coated silica particles showed good photocatalytic performance in degradation of methyl orange aqueous solution under UV light.Graphical abstractA new type of h-SiO2/TiO2 core/shell microspheres exhibited excellent photocatalytic activity was prepared using carboxyl group modified silica particle as core and anatase titania as shell.Research highlights► Surface of h-SiO2 was modified by carboxyl moieties via thiol-ene click reaction. ► The carboxyl groups promoted the formation of a dense and smooth titania layer under well control. ► Anatase titania shell showed good photocatalytic performance in degradation of methyl orange.
Co-reporter:Xiao-Jie Song, Jun Hu, Chang-Chun Wang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2011 380(1–3) pp: 250-256
Publication Date(Web):
DOI:10.1016/j.colsurfa.2011.02.024
Co-reporter:Ju-Mei Li, Wan-Fu Ma, Chuan Wei, Li-Jun You, Jia Guo, Jun Hu, and Chang-Chun Wang
Langmuir 2011 Volume 27(Issue 23) pp:14539-14544
Publication Date(Web):October 19, 2011
DOI:10.1021/la203049k
A systematic study for the preparation of Ag nanoparticle (Ag-NP) coated poly(styrene-co-acrylic acid) (PSA) composite nanospheres by in situ chemical reduction is reported. The experimental results showed that the reaction temperature and the surface coverage of the −COOH determined the surface coverage and grain size of Ag nanoparticles on the PSA nanospheres. The surface enhanced Raman spectroscopy (SERS) sensitivity was investigated using 4-hydroxythiophenol (4-HBT) as the model probe in the solution of composite nanospheres stabilized by polyvinylpyrrolidone (PSA/Ag-NPs/PVP), with the detection limit of about 1 × 10–6 M. Potential application of the new SERS substrate was demonstrated with the detection of melamine, and the detection limit was about 1 × 10–3 M. Chemical noises from PVP and other impurities were observed and attributed mainly to the competitive adsorption of PVP on the surfaces of Ag-NPs. After tetrahydrofuran washing of the PSA/Ag-NPs/PVP substrates that removed the PVP and other residuals, the signal/noise levels of SERS were greatly improved and the detection limit of melamine was determined to be 1 × 10–7 M. This result indicated that the new PSA/Ag-NPs system is highly effective and can be used as the SERS-active substrate for trace analysis of a variety of drugs and food additives.
Co-reporter:Peng Yang;Wei Chen;Changchun Wang
Frontiers of Chemistry in China 2011 Volume 6( Issue 1) pp:9-14
Publication Date(Web):2011 March
DOI:10.1007/s11458-011-0222-0
Biocompatible magnetic nanoparticles were prepared by co-precipitation method in the presence of poly (aspartic acid) (PAsp) as stabilizer, which was one of the most extensively studied and used poly(amino acids). As a biocompatible dispersant, PAsp was successfully attached to the Fe3O4 nanoparticles, which was approved by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). From X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) measurement results, it was found that PAsp stabilized iron oxide nanoparticles possess excellent Fe3O4 crystal structure and superparamagnetic property. Compared with trisodium citrate stabilized magnetic nanoparticles, PAsp stabilized magnetic nanoparticles were biocompatible and with lower cytotoxicity, which makes it more applicable in medicine, biology and biomaterial science.
Co-reporter:Wanfu Ma;Shuai Xu;Jumei Li;Jia Guo;Yao Lin;Changchun Wang
Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 12) pp:2725-2733
Publication Date(Web):
DOI:10.1002/pola.24705
Abstract
A facile and effective approach to preparation of dual-responsive magnetic core/shell composite microspheres is reported. The magnetite(Fe3O4)/poly(methacrylic acid) (PMAA) composite microspheres were synthesized through encapsulating γ-methacryloxypropyltrimethoxysilane (MPS)-modified magnetite colloid nanocrystal clusters (MCNCs) with crosslinked PMAA shell. First, the 200-nm-sized MCNCs were fabricated through solvothermal reaction, and then the MCNCs were modified with MPS to form active vinyl groups on the surface of MCNCs, and finally, a pH-responsive shell of PMAA was coated onto the surface of MCNCs by distillation-precipitation polymerization. The transmission electron microscopy (TEM) and vibrating sample magnetometer characterization showed that the obtained composite microspheres had well-defined core/shell structure and high saturation magnetization value (35 emu/g). The experimental results indicated that the thickness and degree of crosslinking of PMAA shell could be well-controlled. The pH-induced change in size exhibited by the core/shell microspheres reflected the PMAA shell contained large amount of carboxyl groups. The carboxyl groups and high saturation magnetization make these microspheres have a great potential in biomolecule separation and drug carriers. Moreover, we also demonstrated that other magnetic polymeric microspheres, such as Fe3O4/PAA, Fe3O4/PAM, and Fe3O4/PNIPAM, could be synthesized by this approach. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Co-reporter:Bin Luo, Shuai Xu, An Luo, Wen-Rui Wang, Shi-Long Wang, Jia Guo, Yao Lin, Dong-Yuan Zhao, and Chang-Chun Wang
ACS Nano 2011 Volume 5(Issue 2) pp:1428
Publication Date(Web):February 1, 2011
DOI:10.1021/nn103213y
Fabrication of magnetic particles (MPs) with high magnetization and large surface area simultaneously is critical for the application of MPs in bioseparation and drug delivery but remains a challenge. In this article, we describe an unprecedented approach to synthesize mesoporous magnetic colloidal nanocrystal clusters (MCNCs) stabilized by poly(γ-glutamic acid) (PGA) with high magnetization, large surface area (136 m2/g) and pore volume (0.57 cm3/g), excellent colloidal stability, prominent biocompatibility, and acid degradability. This result provides the important step toward the construction of a new family of MCNCs and demonstrates its capacity in a “magnetic motor” drug delivery system. Here, as an example, we explore the applicability of as-prepared mesoporous MCNCs as hydrophobic drug delivery vehicles (paclitaxel as model drug), and the resultant loading capacity is as high as 35.0 wt %. The antitumor efficacy measured by MTT assay is significantly enhanced, compared with free drugs. Thus, combined with their inherent high magnetization, the mesoporous MCNCs pave the way for applying magnetic targeting drug carriers in antitumor therapeutics.Keywords (): biocompatibility; colloidal stability; hydrophobic drug delivery; magnetic colloidal nanocrystal clusters; mesoporosity
Co-reporter:Bin Luo, Shuai Xu, Wan-Fu Ma, Wen-Rui Wang, Shi-Long Wang, Jia Guo, Wu-Li Yang, Jian-Hua Hu and Chang-Chun Wang
Journal of Materials Chemistry A 2010 vol. 20(Issue 34) pp:7107-7113
Publication Date(Web):02 Jul 2010
DOI:10.1039/C0JM00726A
A facile and simple route is employed to synthesise a new type of magnetite hollow porous nanocrystal shells (HPNSs) as hydrophobic drug delivery vehicles. The morphological evolution of spherical clusters from solid to hollow porous shells is controlled in a straightforward fashion through the reaction time. The obtained magnetite HPNSs possesses high magnetization, well-defined structure, and porous shell, the channels and cavity in HPNSs benefit the drug storage, delivery, and release. The structure of HPNSs was characterized by SEM, TEM and XRD, VSM (vibrating sample magnetometer) data showed that the saturation magnetization values of the Fe3O4 HPNSs are 67.5, 73.2, 79.4, and 88.7 emu/g, corresponding to reaction times of 6, 8, 12, and 16.5 h, respectively. This result clearly proved that the crystallinity could be improved by Ostwald ripening of nanocrystals through a dissolution–recrystallization process, the formation of the hollow porous structure was promoted as well. FT-IR and TGA results showed that the porous shell facilitated paclitaxel diffusion into the cavity of hollow structure, and the drug loading of magnetite HPNSs for paclitaxel is very high (20.2 wt%). The antitumor efficacy of the drug-loaded HPNSs measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was clearly enhanced, compared with free drugs.
Co-reporter:Junjun Li;Feng Yang;Guiquan Guo;Dong Yang;Jiang Long;Deliang Fu;Jennifer Lu;Changchun Wang
Polymer International 2010 Volume 59( Issue 2) pp:169-174
Publication Date(Web):
DOI:10.1002/pi.2703
Abstract
Carbon nanotubes (CNTs) are capable of traversing cellular membranes by endocytosis and are therefore promising materials for use in imaging and drug delivery. Unfortunately, pristine CNTs are practically insoluble and tend to accumulate inside cells, organs and tissues. To overcome the poor dispersibility and toxicity of pristine CNTs, hydrophilic functionalization of CNTs has been intensively investigated. Water-soluble multi-walled carbon nanotubes (MWCNTs) were prepared by in situ polymerization of acrylic acid in a poor solvent for poly(acrylic acid) (PAA). The solvent type influenced the grafted density and chain length of PAA. MWCNTs with a high grafted density of PAA (22 wt%) could be well dispersed in water, NaCl aqueous solution (0.9 wt%) and cell culture media. The in vitro cytotoxicity of these MWCNTs for endothelial cells is reasonably low even at high concentration of PAA-g-MWCNT (70 µg mL−1). The experimental results show that the biocompatibility of these MWCNTs is sufficient for biological applications. PAA-g-MWCNTs were successfully utilized for lymph node tracing. Experimental results suggest that PAA-g-MWCNTs have potential to be used as a vital staining dye, which may simplify the identification of lymph nodes during surgery. Copyright © 2009 Society of Chemical Industry
Co-reporter:Bin Luo, Xiao-Jie Song, Feng Zhang, Ao Xia, Wu-Li Yang, Jian-Hua Hu and Chang-Chun Wang
Langmuir 2010 Volume 26(Issue 3) pp:1674-1679
Publication Date(Web):September 15, 2009
DOI:10.1021/la902635k
Monodisperse organic/inorganic composite microspheres with well-defined structure were prepared through the encapsulation of silica coated superparamagnetic magnetite colloidal nanoparticle clusters (CNCs) with cross-linked poly(N-isopropylacrylamide) (PNIPAM) shell. At first, the sub-micrometer-sized CNCs were fabricated by the solvothermal process, and then a silica layer was coated on the surface of CNCs through a sol−gel process, and finally, a thermoresponsive shell of PNIPAM was deposited onto the surface of the core/shell magnetic microspheres by a precipitation polymerization. The experimental results showed that the size of Fe3O4 core, the thickness of SiO2 shell, as well as volume phase transition temperature (VPTT) of PNIPAM shell could be well controlled, and this structured modulation could satisfy different requirements. The superparamagnetic behavior, high magnetization (the saturation magnetization of Fe3O4/SiO2/PNIPAM microspheres with a 10% cross-linking density is 41.6 emu/g), and good thermosensitivity make these composite microspheres an ideal candidate for various important applications such as in controlled drug delivery, bioseparation, and catalysis.
Co-reporter:Dong Yang, Feng Yang, Jianhua Hu, Jiang Long, Changchun Wang, Deliang Fu and Quanxing Ni
Chemical Communications 2009 (Issue 29) pp:4447-4449
Publication Date(Web):12 Jun 2009
DOI:10.1039/B908012K
Hydrophilic multi-walled carbon nanotubes decorated with magnetite nanoparticles were readily taken up into lymph vessels and delivered gemcitabine to lymph nodes with high efficiency under the guidance of a magnetic field.
Co-reporter:Yuechao Tang, Dong Yang, Feng Qin, Jianhua Hu, Changchun Wang, Hualong Xu
Journal of Solid State Chemistry 2009 Volume 182(Issue 8) pp:2279-2284
Publication Date(Web):August 2009
DOI:10.1016/j.jssc.2009.05.036
The nanocomposites of multi-walled carbon nanotubes (MWNTs) decorated with nickel nanoparticles were conveniently prepared by a chemical reduction of nickel salt in the present of poly(acrylic acid) grafted MWNTs (PAA-g-MWNTs). Due to the strong interaction between Ni2+ and –COOH, PAA-g-MWNTs became an excellent supporting material for Ni nanoparticles. The morphology and distribution of Ni nanoparticles on the surface of MWNTs were greatly influenced by the reduction temperatures, the experimental results also showed that the distribution of Ni nanoparticles was greatly improved while the MWNTs were modified by poly(acrylic acid) (PAA). The hydrogenation activity and selectivity of MWNTs decorated with Ni nanoparticles (Ni-MWNTs) for α, β-unsaturated aldehyde (citral) were also studied, and the experimental results showed that the citronellal, an important raw material for flavoring and perfumery industries, is the favorable product with a percentage as high as 86.9%, which is 7 times higher than that of catalyst by Ni-supported active carbon (Ni-AC).Nickel nanoparticles decorated multi-walled carbon nanotubes (Ni-MWNTs) nanocomposites were conveniently prepared by a chemical reduction of nickel salt in the present of poly(acrylic acid) grafted MWNTs (PAA-g-MWNTs). These nanocomposites possessed excellent catalytic activity and selectivity for hydrogenation of citral.
Co-reporter:Tao Gong, Dong Yang, Jianghua Hu, Wuli Yang, Changchun Wang, Jennifer Qing Lu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 339(1–3) pp:232-239
Publication Date(Web):1 May 2009
DOI:10.1016/j.colsurfa.2009.02.034
Hybrid nanospheres with controllable magnetite content and narrow size distribution, composed of Fe3O4 nanoparticles encapsulated in a crosslinked polystyrene matrix, were synthesized by magneto-template (Fe3O4 minidroplets) miniemulsion polymerization. In this process, a magnetic fluid (ferrofluid), consisting of Fe3O4 nanoparticles dispersed in octane, was directly emulsified in the presence of sodium dodecyl sulfate under ultrasonication. The formation of Fe3O4 minidroplets served as a template (magneto-template) for the subsequent miniemulsion polymerization. Transmission electron microscopy (TEM) images showed uniform hybrid nanospheres in which the Fe3O4 nanoparticles were evenly dispersed. The average size of these magnetic hybrid nanospheres can be rationally adjusted from 70 nm to 130 nm by varying the amount of surfactant. The magnetite content can be controlled over a wide range, from 40 wt % to 70 wt %, by modulating the dosage of the ferrofluid. Real-time monitoring of the size of the Fe3O4 minidroplets after addition of monomers indicated gradual incorporation of monomers into the magneto-template prior to polymerization. The use of divinyl benzene with styrene to crosslink the polymer matrix was used for enhancing the integrity of the hybrid nanospheres. These magnetic hybrid nanospheres are superparamagnetic, and thus are ideal candidates for biomedical applications after suitable surface modification.
Co-reporter:Feng Zhang and Chang-Chun Wang
Langmuir 2009 Volume 25(Issue 14) pp:8255-8262
Publication Date(Web):April 6, 2009
DOI:10.1021/la9004467
P(NIPAM-co-AA) microcontainers surface-anchored with magnetic nanoparticles were prepared using PSt/P(NIPAM-co-AA) core/shell microspheres and amino-modified Fe3O4@SiO2 particles as building blocks. At first, the PSt/P(NIPAM-co-AA) core/shell microspheres were prepared by seeded emulsion polymerization, and the amino-modified Fe3O4@SiO2 particles were prepared by a modified Stöber method followed by functionalized by 3-aminopropyltriethoxysilane. Then, the smaller amino-modified Fe3O4@SiO2 particles were assembled onto the surface of PSt/P(NIPAM-co-AA) core/shell microspheres by electrostatic interaction. Subsequently, the two particles were permanently combined through amidation reaction between carboxylic groups and amino groups under the catalysis of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide. By dissolving the PSt core with tetrahydrofuran, novel triple-functional microcontainers with superparamagnetism and pH and temperature sensitivity were obtained.
Co-reporter:Yuan-Yuan Yu;Feng Tian;Chuan Wei
Journal of Polymer Science Part A: Polymer Chemistry 2009 Volume 47( Issue 11) pp:2763-2773
Publication Date(Web):
DOI:10.1002/pola.23357
Abstract
A series of poly(N-isopropylacrylamide-co-N-hydroxymethylacrylamide) P(NIPAM-co-NHMA) copolymers were firstly synthesized via free radical polymerization. Then, the hydrophobic, photosensitive 2-diazo-1,2-naphthoquinone (DNQ) molecules were partially and randomly grafted onto P(NIPAM-co-NHMA) backbone through esterification to obtain a triple-stimuli (photo/pH/thermo) responsive copolymers of P(NIPAM-co-NHMA-co-DNQMA). UV-vis spectra showed that the lower critical solution temperature (LCST) of P(NIPAM-co-NHMA) ascended with increasing hydrophilic comonomer NHMA molar fraction and can be tailored by pH variation as well. The LCST of the P(NIPAM-co-NHMA) went down firstly after DNQ modification and subsequently shifted to higher value after UV irradiation. Meanwhile, the phase transition profile of P(NIPAM-co-NHMA-co-DNQMA) could be triggered by pH and UV light as expected. Thus, a triple-stimuli responsive copolymer whose solution properties could be, respectively, modulated by temperature, light, and pH, has been achieved. These stimuli-responsive properties should be very important for controlled release delivery system. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2763–2773, 2009
Co-reporter:Yiwen Chu, Peng Zhang, Jianghua Hu, Wuli Yang and Changchun Wang
The Journal of Physical Chemistry C 2009 Volume 113(Issue 10) pp:4047-4052
Publication Date(Web):2017-2-22
DOI:10.1021/jp810395j
Through the complexation of cyano groups in polyacrylonitrile (PAN) microspheres with cobalt (iron) ions under mild conditions, cobalt (iron)-containing PAN microspheres could be prepared effectively, then after pyrolyzation of the composite microspheres at 800 °C under N2 atmosphere, Co(Fe)/carbon nanocomposite microspheres could be prepared, and the metal content is up to ∼71 wt % in the Co(Fe)/carbon nanocomposite microspheres. Thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry investigation proved that almost all the cobalt nanoparticles were embedded in the interior of the carbon microspheres, which protected the metal nanocrystals (Co or Fe) from oxidation. The microspheres possess high magnetization (Ms is up to ∼161 emu/g) and show near-zero remanence and coercivity (Hc is down to ∼0.012 KOe) at room temperature, suggesting that they are outstanding soft ferromagnets with high magnetic susceptibilities and practically nil hysteresis loss.
Co-reporter:Guiquan Guo, Feng Qin, Dong Yang, Changchun Wang, Hualong Xu and Shu Yang
Chemistry of Materials 2008 Volume 20(Issue 6) pp:2291
Publication Date(Web):February 16, 2008
DOI:10.1021/cm703225p
Crystalline Pt nanoparticles were electrolessly deposited on poly(acrylic acid) (PAA) grafted multiwalled carbon nanotubes (MWNTs). The density and uniformity of Pt nanoparticles on MWNTs were found dependent on the PAA grafting density, while their morphologies were tailored by the addition of NO3− and Cu2+ ions. The catalytic activity and selectivity of hydrogenation of α,β-unsaturated aldehyde, citral, on Pt/MWNTs nanocomposites with different morphologies was studied. The irregularly shaped polycrystalline Pt nanoparticles showed the highest conversion of citral, 92.2%, in comparison to 24.7% from Pt/active carbon, 45.0%, and 40.4% from polyhedrons and polypods Pt single crystals on MWNTs, respectively. The unusually high conversion on Pt/MWNTs suggests a synergistic effect between the PAA grafted MWNTs and the Pt nanoparticles. In the study of the selectivity of hydrogenation, tetra- and octahedron Pt nanoparticles showed the highest ratio of geraniol/nerol, 5.2, ∼3 times higher than that of Pt/active carbon, whereas those of irregularly shaped polycrystalline and tetra- and octapods of single crystalline Pt on the MWNTs are 1.9 and 2.2, respectively. Electron diffraction patterns revealed that in the case of tetra- and octahedral Pt particles on the MWNT surface only the {111} facet was exposed, which might induce steric hindrance for the cis-isomers but not for the trans-isomers, whereas the {111} facets were deformed in tetrapods and octapods.
Co-reporter:Dong Yang, Guiquan Guo, Jianhua Hu, Changchun Wang and Donglin Jiang
Journal of Materials Chemistry A 2008 vol. 18(Issue 3) pp:350-354
Publication Date(Web):22 Nov 2007
DOI:10.1039/B713467C
Multi-walled carbon nanotubes (MWNTs) bearing hydroxyl groups (MWNTols) on the exterior surface have been synthesized by an alkaline-mediated hydrothermal treatment of MWNTs under autogenous pressure at 180 °C. X-Ray photoelectron spectroscopy shows that the content of hydroxyl groups increases with the concentration of sodium hydroxide utilized. FT-IR spectroscopy shows that hemiketals were incorporated into the structure of MWNTols. The prepared MWNTols are highly soluble in polar solvents such as water, methanol, butanone and tetrahydrofuran, to give robust stable black solutions. Transmission electron microscopy reveals that the diameter, length and morphology of MWNTs are well retained in MWNTols. MWNTols are redox active on their exterior surface, where hydroxyl groups, upon reaction with Ce(IV) ions, transform to radical species and initiate polymerization of N-isopropylacrylamide (NIPAM).
Co-reporter:Dandan Shao, Ao Xia, Jianhua Hu, Changhcun Wang, Weiming Yu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2008 Volume 322(1–3) pp:61-65
Publication Date(Web):5 June 2008
DOI:10.1016/j.colsurfa.2008.02.023
This paper describes a new method for preparation of superparamagnetic magnetite/silica composite microspheres by modified miniemulsion polymerization. The reaction parameters on shape, size and uniformity of the nanomicrospheres were studied. Through changing the dosage of iron oxide, the composite microspheres with different magnetite content from 10 wt% to 30 wt% could be prepared, and the response to magnetic field is tunable depending on the magnetite loading. Under the optimized condition, the prepared composite microspheres have the character of monodispersity and quick magnetic response. This characteristic is critical for the application in biomolecular separations. The separation experiment for plasmid DNA showed that the composite microspheres possess stronger magnetic response compared with commercialized reagent.
Co-reporter:Feng Zhang
Colloid and Polymer Science 2008 Volume 286( Issue 8-9) pp:889-895
Publication Date(Web):2008 August
DOI:10.1007/s00396-008-1842-x
A reliable and efficient route for preparing thermoresponsive hollow microgels based on cross-linked poly(N-isopropyl acrylamide) (PNIPAM) was developed. Firstly, monodisperse thermoresponsive core–shell microspheres composed of a P(styrene (St)-co-NIPAM) core and a cross-linked PNIPAM shell were prepared by seeded emulsion polymerization using P(St-co-NIPAM) particles as seeds. The size of the P(St-co-NIPAM) core can be conveniently tuned by different dosages of sodium dodecyl sulfate. The thickness of the cross-linked PNIPAM shell can be controlled by varying the dosage of NIPAM in the preparation of PNIAPM shell. Then, hollow PNIPAM microgels were obtained by simply dissolving the P(St-co-NIPAM) core with tetrahydrofuran. The core–shell microspheres and the hollow microgels were characterized by transmission electron microscopy, dynamic light scattering, atomic force microscopy, and Fourier-transform infrared spectroscopy.
Co-reporter:Feng Zhang
The Journal of Physical Chemistry C 2008 Volume 112(Issue 39) pp:15151-15156
Publication Date(Web):September 10, 2008
DOI:10.1021/jp804452r
Weakly ferromagnetic iron oxide nanoparticles with narrow size distribution were prepared by a high-temperature hydrolysis reaction. The magnetic nanoparticles can self-assemble into one-dimensional particle chains on substrates as well as in colloid dispersion through magnetic dipolar interaction without the help of an applied magnetic field. The 1D assemblies were further harnessed to prepare 1D nanostructures with aligned magnetic nanoparticle inclusions and a continuous silica shell. One-dimensional iron oxide/silica nanostructures were prepared through chainlike self-assembly of the magnetic nanoparticles in a mixture of ethanol, ammonia, and water followed by a sol−gel process of TEOS at the surface of the assemblies. The length of the nanostructures can be controlled by the amplitude of ultrasonication, and the thickness of the silica coating can be tuned by the dosage of TEOS. The 1D nanostructures exhibit highly magnetic sensitivity. In the presence of an applied magnetic field, the nanostructures can be oriented and align along the direction of the external magnetic field.
Co-reporter:Lan Jin;Hongbo Liu;Wuli Yang;Changchun Wang;Kui Yu
Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 9) pp:2948-2959
Publication Date(Web):
DOI:10.1002/pola.22629
Abstract
This manuscript reports on a novel synthetic approach to engineer water-dispersible microspheres with short poly(amidoamine) (PAMAM) chain grafted on their surface. These core-shell polymeric microspheres have a large amount of amine groups on their surface obtained via “starburst” reactions. First, monodispersed poly (methyl methacrylate)-co-poly(glycidyl methacrylate) (P(MMA/GMA)) microspheres were prepared by surfactant-free emulsion polymerization. Afterwards, Michael reaction and subsequent amidation reactions were carried out repetitively to synthesize arborescent PAMAM chains grafted on the surface of the P(MMA/GMA) microspheres. The resulting PAMAM-grafted microspheres exhibit good dispersibility in aqueous environments. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) demonstrate the successful grafting; furthermore, the crosslink degree of the P(MMA/GMA) microspheres as well as the PAMAM chain length affect the stability of the resulting core-shell microspheres, as experimentally tested by heat treatment and acidic treatment. Easily, the PAMAM chains are protonated at low pH, and are thus able to effectively adsorb negatively-charged magnetic nanoparticles. Bright photoluminescent (PL) water-dispersible polymeric microspheres are fabricated readily via the reaction of the surface amine groups and traditional fluorescent molecules, namely fluorescein isothiocyanate (FITC). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2948–2959, 2008
Co-reporter:Feng Tian, Yuanyuan Yu, Changchun Wang and Shu Yang
Macromolecules 2008 Volume 41(Issue 10) pp:3385-3388
Publication Date(Web):May 2, 2008
DOI:10.1021/ma800142j
Co-reporter:Zhizhong Xu, Ao Xia, Changchun Wang, Wuli Yang, Shoukuang Fu
Materials Chemistry and Physics 2007 Volume 103(2–3) pp:494-499
Publication Date(Web):15 June 2007
DOI:10.1016/j.matchemphys.2007.02.074
Raspberry-like magnetic polystyrene microspheres were prepared via soap-free emulsion polymerization using 2,2′-azobis(2-methylpropionamidine) dihydrochloride (V50) as initiator. The effect of polymerization parameters, such as initiator type, initiator content and the feeding sequence on the particle size and morphology of magnetic polystyrene microspheres, were examined. The final magnetic polystyrene microspheres were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The experimental results showed that V50 was a suitable initiator for preparation of raspberry-like magnetic polystyrene microspheres.
Co-reporter:Changchun Wang;Wuli Yang;Jianhua Hu;Fang Wang
Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 20) pp:4552-4563
Publication Date(Web):29 AUG 2007
DOI:10.1002/pola.22161
Polymeric particles with hydrophobic PCL hairy chains were prepared by ring-opening polymerization (ROP) from hydrophilic core particles, which were prepared by soap-free emulsion polymerization of styrene, 2-hydroxyethyl methacrylate, and divinylbenzene. Due to the incorporation of 2-hydroxyethyl methacrylate in the core particles, hydroxyl groups on the surface of core particles could be obtained, and in the following ROP of ε-caprolactone, the hydroxyl groups on the surface of the particles could effectively initiate the polymerization. Various reaction conditions were evaluated to produce hairy particles with optimal grafting efficiency. The presence of hydrophobic polymeric hairs on the surface of particles led to a dramatic improvement in their dispersibility in oil phase. By controlling the grafting amount of PCL on the surface of hydrophilic core particles, the surface properties of the hairy particles could be well tailored, represented the change of water contact angles from 75.0° to 114.6°. The prepared hairy particles were characterized by thermogravimetric analysis, scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared analysis. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4552–4563, 2007
Co-reporter:Xiali Zhang;Dong Yang;Peng Xu;Changchun Wang
Journal of Materials Science 2007 Volume 42( Issue 17) pp:7069-7075
Publication Date(Web):2007 September
DOI:10.1007/s10853-007-1536-7
Inverse gas chromatography (IGC) was used to characterize the surface properties of pristine multi-walled carbon nanotubes (MWNTs), as well as the poly(acrylic acid) sidewall covalently functionalized MWNTs (PAA-g-MWNTs) and hydroxyl group directly grafted MWNTs (MWNTols). The dispersive component of the surface energy (
\( \gamma _S^D \)) and the acid/base character of these samples’ surfaces were estimated by the retention time with different non-polar and polar probes at infinite dilution region. The specific free energy (ΔGAB) and the enthalpy (ΔHAB) of adsorption corresponding to acid–base surface interactions were determined. By correlating ΔHAB with the donor and acceptor numbers of the probes, the acidic (KA) and the basic KD parameters of the samples’ were calculated. The results show that chemical modification successfully reduces the dispersive component of the surface energy of MWNTs. Furthermore, MWNTs grafted with hydroxyl groups exhibit a more basic character, while MWNTs grafted with poly(acrylic acid) show a more acidic character. Overall, IGC provides useful complementary information on the changes resulted from the chemical modifications of the surface.
Co-reporter:Ke Min;Jin Lan;Jianhuan Hu;Changchun Wang
Polymers for Advanced Technologies 2006 Volume 17(Issue 7‐8) pp:491-493
Publication Date(Web):9 AUG 2006
DOI:10.1002/pat.749
Monodispersed OEGMA/St polymeric particles were prepared through soap-free emulsion polymerization, then surface modification was conducted by atom transfer radical polymerization (ATRP), and nano-size hairy shell of OEGMA/St particles were obtained. By hydrolysis, the grafting chains of the hairy particles were successfully cut down from the core particles. Through gel permeation chromatography (GPC) and transmission electron microscopy (TEM) measurements, the density of grafting chains was calculated. Experimental results showed that the hairy shell on the surface of the particles could dramatically improve the particles dispersibility in organic solvents. Copyright © 2006 John Wiley & Sons, Ltd.
Co-reporter:Haoran Chen, Tongyu Chen, Jianhua Hu, Changchun Wang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2005 Volume 268(1–3) pp:24-29
Publication Date(Web):31 October 2005
DOI:10.1016/j.colsurfa.2005.05.013
Amphiphilic graft copolymers composed of poly(hydroxyethyl aspartamide)-co-propyl aspartamide) (PHEA-PA) as the hydrophilic backbone and poly(lactide) (PLA) as the hydrophobic side chain were successfully synthesized by grafting lactide (LTD) onto PHEA-PA. Polysuccinimide (PSI) was firstly synthesized from l-aspartic acid through thermal condensation polymerization method, and then followed by two-step aminolysis processes to form PHEA-PA with different amounts of hydroxyl groups. The hydroxyl groups were then used as initial points to graft PLA onto PHEA-PA backbone via a ring-opening polymerization in the presence of Sn(Oct)2. The grafting reaction of PLA onto PHEA-PA was confirmed by 1H NMR, FT-IR, and DSC. Micelle-like aggregates were obtained when the amphiphilic comb-like copolymer solution of DMF was added into an excessive amount of water. Strong hydrophobic intramolecular and intermolecular association of PLA chains led to aggregates with hydrophobic microdomains. The dispersion of the self-aggregates of poly(hydroxyethyl aspartamide-co-propyl aspartamide)-g-poly(d,l-lactide) (PHEA-PA-g-PLA) copolymers is stable in aqueous medium. Spherical aggregates of PHEA-PA-g-PLA were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), the diameters were about 100 nm.
Co-reporter:Changchun Wang, Zhi-Xin Guo, Shoukuan Fu, Wei Wu, Daoben Zhu
Progress in Polymer Science 2004 Volume 29(Issue 11) pp:1079-1141
Publication Date(Web):November 2004
DOI:10.1016/j.progpolymsci.2004.08.001
This review deals with recent progress in studies of polymeric covalent and noncovalent modifications of fullerenes (mainly C60) and carbon nanotubes (CNTs), and their applications. By using functional polymers to react with fullerenes, or synthesizing polymers in the presence of fullerenes, various kinds of polymeric fullerenes can be prepared: side-chain polymers, main-chain polymers, dendritic fullerenes, star-shaped polymers, fullerene end-capped polymers, etc. Furthermore, by controlling the functional groups in polymer chains and reaction conditions, many well-defined fullerene polymers have been prepared. ‘Living’ polymerization methods have also been introduced for preparation of fullerene polymers, e.g. anionic polymerization, iniferter technique, stable free radical polymerization, and atom-transfer free-radical polymerisation. With these living methods, both the architecture of the fullerene polymers and the grafted polymer chains can be well-controlled. All of these methods establish a good platform for developing applications of fullerene polymers. The synthesis of polymeric CNTs is only in its infancy. However, present results show promise that the combination of the unique properties of CNTs with functional polymers will lead to novel materials with unusual mechanical, electrical, magnetic, and optical properties. Doping of polymeric systems with fullerenes in is also a very important research area, especially for preparation of electronic and optical materials. Both conducting and conventional polymers can be used as matrices in the preparation of functional composites. The structures and properties of these composites are strongly dependent on the properties and concentrations of the active components. CNT-doped polymers have also been prepared and show interesting properties. The combination of the unique properties of fullerenes and CNTs with polymers makes these materials potential candidates for many applications, such as data storage media, photovoltaic cells and photodiodes, optical limiting devices, photosensitive drums for printers, and so on. The applications of polymeric fullerenes and CNTs are also reviewed in this article.
Co-reporter:Yujun Qin;Changchun Wang;Junwei Yang;Jianhua Hu;Zhixin Guo
Macromolecular Materials and Engineering 2004 Volume 289(Issue 9) pp:828-832
Publication Date(Web):26 AUG 2004
DOI:10.1002/mame.200400049
Summary: Soluble multi-walled carbon nanotubes (s-MWNTs), obtained via amidation reaction of octadecylamine with purified multi-walled carbon nanotubes (p-MWNTs), were solution-mixed with P(MMA-co-EMA) at various loadings. Compared to the p-MWNTs/P(MMA-co-EMA) composites, the s-MWNTs/P(MMA-co-EMA) composites showed great improvement both in Young's modulus and tensile strength. With the addition of 10 wt.-% s-MWNTs, the Young's modulus and tensile strength of s-MWNTs/P(MMA-co-EMA) composite have 135% and 49% increase over the pure P(MMA-co-EMA), respectively, and a 9.2% increase in Young's modulus and 12.8% increase in tensile strength over that of 10 wt.-% p-MWNTs composite. With the increase of MWNTs content, the Tg increases from 89 to 106 °C. SEM studies show that the s-MWNTs are well dispersed in the polymer matrix. Good dispersion of s-MWNTs in polymer matrix and great interfacial bonding between s-MWNTs and P(MMA-co-EMA) may be the key reason for the improvement of the mechanical properties.
Co-reporter:Ping Liu;Lan Jin;Jianhua Hu;Changchun Wang
Polymer International 2004 Volume 53(Issue 2) pp:
Publication Date(Web):21 OCT 2003
DOI:10.1002/pi.1327
Well-defined methyl methacrylate (MMA) and 2-(trimethylsiloxy)ethyl methacrylate (Pro-HEMA) copolymers were prepared by atom-transfer radical polymerization(ATRP), using CuCl/2,2′-bipyridine as catalytic system and p-toluenesulfonyl chloride as initiator. ATRP process of MMA and Pro-HEMA was monitored by 1H NMR, and the kinetic curves of the MMA/Pro-HEMA copolymerization were plotted in terms of the 1H NMR data. At low content of Pro-HEMA in the feed composition, the copolymerization can be well controlled with the molecular weight, polydispersity and the monomer distribution in the copolymer chain. With the increase of Pro-HEMA content in the feed mixture, the composition of the final copolymer deviates from the composition of the feed mixture gradually, and gradient copolymers of MMA/Pro-HEMA can be obtained. Through the hydrolysis process, well-defined copolymers of MMA/HEMA were obtained from poly(MMA/Pro-HEMA). Copyright © 2003 Society of Chemical Industry
Co-reporter:Dong Yang, Lang Li, Changchun Wang
Materials Chemistry and Physics 2004 Volume 87(Issue 1) pp:114-119
Publication Date(Web):September 2004
DOI:10.1016/j.matchemphys.2004.05.003
Atom transfer radical polymerization (ATRP) catalyzed by N,N′,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr was performed to synthesize poly (tert-butyl acrylate) (PtBA-Br) with predesigned molecular weight and narrow polydispersity. Using the PtBA-Br as macroinitiator, the PtBA-block-PS copolymer was prepared through ATRP. After terminated bromine atom was converted to end-functional azide group (P(tBA-b-St)-N3), C60 end-capped PtBA-PS block copolymers (P(tBA-b-St)-C60) were synthesized by reacting C60 with P(tBA-b-St)-N3. GPC characterizations showed that C60 was chemically bonded to the end of P(tBA-b-St) chain and the products were mono-substituted. FT-IR, UV-Vis measurements confirmed that hydrolysis of P(tBA-b-St)-C60 resulted in amphiphilic C60 end-capped PAA-PS block copolymers. In additional, the photoconductivity of P(tBA-b-St)-C60 was measured.
Co-reporter:Changchun Wang;Frank N. Jones
Journal of Applied Polymer Science 2000 Volume 78(Issue 9) pp:1698-1706
Publication Date(Web):18 SEP 2000
DOI:10.1002/1097-4628(20001128)78:9<1698::AID-APP160>3.0.CO;2-J
A series of tung oil modified soybean alkyd emulsions are prepared by an inversion emulsified technique. In these alkyd resins, the tung oil contents are about 0, 12.5, and 25.0 wt % (based on the total oil). Using IGEPAL CO-630 as the surfactant, a very stable alkyd emulsion can be obtained. With the increase of the tung oil contents in alkyd emulsions, the initial droplet sizes of the emulsions increase dramatically. Aging under 50°C can eliminate the difference in droplet sizes; the final droplet sizes of the emulsions are about 50 nm. The alkyd resins also have good hydrolytic stability. The tung oil contents in the alkyd resins also strongly influences the film properties; suitable tung oil content improves the film gloss. An atomic force microscopy investigation shows that the film from the alkyd emulsion is more water sensitive; after a 50-h deionized water immersion, the film surface appears to have a lot of dents. This indicates that the film surface may be very rich in surfactant species. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1698–1706, 2000
Co-reporter:Peng Yang, Xianfu Luo, Sheng Wang, Fang Wang, Chuanbing Tang, Changchun Wang
Colloids and Surfaces B: Biointerfaces (1 March 2017) Volume 151() pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.colsurfb.2016.12.037
•Uniform biodegradable yolk-shell Fe3O4@PFH@PMAA-DOX microspheres.•Robust dual-modality imaging capability for ultrasound and MR.•Control release of DOX under pH, redox and ultrasound stimuli.•Degradation of composite microspheres into short hydrophilic polymer chains and iron ions.A new class of uniform biodegradable yolk-shell Fe3O4@PFH@PMAA-DOX microspheres was developed as ultrasound/MR dual-modality imaging contrast agents and drug delivery system. PMAA shells exhibit excellent drug loading capability and efficiency, the DOX-loading capacity is 15.4 wt% and the drug loading efficiency is 91%. In vivo ultrasound and MRI experiments indicate that the as-prepared Fe3O4@PFH@PMAA-DOX microspheres successfully reach tumor tissues and possess robust dual-modality imaging capability, the r2 value of MRI is 71.82 mM−1 s−1. In vitro cytotoxicity and in vivo tissues biopsies show that the loaded DOX can be control-released under pH, redox and ultrasound multi-stimuli and kill cancer cells effectively. Furthermore, disulfide-crosslinked PMAA shells and PGA-stabilized Fe3O4 cores can be respectively degraded into short hydrophilic polymer chains and iron ions, reducing their cumulative toxicity in organisms. Thus, the multifunctional biodegradable microspheres are safer for normal tissues and more beneficial in actual clinical applications.
Co-reporter:Bin Luo, Shuai Xu, Wan-Fu Ma, Wen-Rui Wang, Shi-Long Wang, Jia Guo, Wu-Li Yang, Jian-Hua Hu and Chang-Chun Wang
Journal of Materials Chemistry A 2010 - vol. 20(Issue 34) pp:NaN7113-7113
Publication Date(Web):2010/07/02
DOI:10.1039/C0JM00726A
A facile and simple route is employed to synthesise a new type of magnetite hollow porous nanocrystal shells (HPNSs) as hydrophobic drug delivery vehicles. The morphological evolution of spherical clusters from solid to hollow porous shells is controlled in a straightforward fashion through the reaction time. The obtained magnetite HPNSs possesses high magnetization, well-defined structure, and porous shell, the channels and cavity in HPNSs benefit the drug storage, delivery, and release. The structure of HPNSs was characterized by SEM, TEM and XRD, VSM (vibrating sample magnetometer) data showed that the saturation magnetization values of the Fe3O4 HPNSs are 67.5, 73.2, 79.4, and 88.7 emu/g, corresponding to reaction times of 6, 8, 12, and 16.5 h, respectively. This result clearly proved that the crystallinity could be improved by Ostwald ripening of nanocrystals through a dissolution–recrystallization process, the formation of the hollow porous structure was promoted as well. FT-IR and TGA results showed that the porous shell facilitated paclitaxel diffusion into the cavity of hollow structure, and the drug loading of magnetite HPNSs for paclitaxel is very high (20.2 wt%). The antitumor efficacy of the drug-loaded HPNSs measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was clearly enhanced, compared with free drugs.
Co-reporter:Ju-Mei Li, Wan-Fu Ma, Chuan Wei, Jia Guo, Jun Hu and Chang-Chun Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 16) pp:NaN5998-5998
Publication Date(Web):2011/03/14
DOI:10.1039/C0JM04343E
A new type of polymer core and silver nanoparticle/silica shell multifunctional composite microsphere is reported. The monodisperse polymer core of poly(styrene-co-acrylic acid), prepared by surfactant-free emulsion polymerization, serves as the supporting template to facilitate the synthesis and handling of the highly functionalized substrates to achieve consistent mechanical and surface chemical properties. The shell of silver nanoparticles, formed in situ by controlled interfacial reduction of AgNO3 with polyvinylpyrrolidone (PVP), serves as the optimal metal enhancer for surface enhanced Raman spectroscopy (SERS). The Ag nanoparticle shell is stabilized with a silica layer using a sol–gel process, which is also functionalizable with reactive epoxides for further bio-conjugation using epoxy ring-opening methods. Preliminary results indicated that the microspheres are easily prepared with exceptional chemical and physical uniformity. SERS experiments with 4-aminobenzenethiol (4-ABT) as the indicator showed that the resulting multifunctional microspheres allowed the production of highly consistent enhancement of the Raman signals down to nM concentrations of 4-ABT, making them highly desirable candidates as the enhancers for high performance SERS analysis and as SERS optical labels in biomedical imaging. The microspheres are robust and the high density of the SERS active Ag nanoparticles on the microspheres provided unique signal averaging for the method to be potentially quantitative which is an urgent goal for SERS substrate design and SERS analysis.
Co-reporter:Wan-Fu Ma, Ke-Yi Wu, Jing Tang, Dian Li, Chuan Wei, Jia Guo, Shi-Long Wang and Chang-Chun Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 30) pp:NaN15214-15214
Publication Date(Web):2012/06/07
DOI:10.1039/C2JM31721D
A smart magnetic targeting drug carrier (MCNC/PAA) comprising an approximately 100 nm sized magnetic colloid nanocrystal cluster (MCNC) core and a pH-responsive cross-linked poly(acrylic acid) (PAA) shell is reported. The abundant carboxyl groups in the shell enable the resultant MCNC/PAA to easily load a large amount of doxorubicin (DOX) (up to 44.6%) via the strong interaction between the DOX and the carboxyl group in a neutral solution. Interestingly, a synergistic pH-responsive effect derived from the entrapped DOX and PAA network was found to effectively manipulate the drug releasing behavior at 37 °C. It was found that the premature release was highly restricted at a pH of 7.4, and upon reduction in pH from 7.4 to 5.0 or 4.0, a large amount of drug was rapidly released. Compared with the synthesized MCNC/PNIPAM, MCNC/PHEMA and MCNC/PDMAPMA nanocarriers, the MCNC/PAA was preferably suited to drug delivery. In addition, the composite nanocarriers could be tracked by magnetic resonance imaging (MRI). The cytotoxicity assay of MCNC/PAA to normal cells indicated that the composite nanospheres were biocompatible and suitable as drug carriers. Meanwhile, the DOX-loaded composite nanospheres had more potent cytotoxicity than free DOX to HeLa cells. These results clearly imply that the MCNC/PAA nanocarrier is a promising platform that can be applied to construct a smart drug delivery system with magnetic targeting and pH-stimulation, as well as tracking by MRI.
Co-reporter:Shuai Xu, Baoru Yin, Jia Guo and Changchun Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 33) pp:NaN4087-4087
Publication Date(Web):2013/06/03
DOI:10.1039/C3TB20238K
Uniform hollow magnetic supraparticles (HMSPs) consisting of nanocrystal aggregates in shells are designed and fabricated via a one-pot microwave irradiation process within 10 min, employing casein, a major milk protein, as a structure-directing agent responsible for the formation of hollow structures. The casein micelle (CM)-mediated self-assembled HMSPs exhibit structural uniformity, excellent aqueous dispersibility, enhanced biocompatibility, as well as a high saturation magnetization (∼70 emu g−1). Herein, CMs serve as soft templates to induce inner hollow cavities through electrostatic interactions between negative CM “brushes” and positive Fe(III) species, and subsequent degradation of the inner cores under microwave irradiation, meanwhile improving the colloidal stability and biocompatibility of the HMSPs. Besides, the interior cavity size of the HMSPs could be readily tuned in the range of 40 nm to 150 nm, simply by varying the feeding dosage of casein. In light of the interior void and desirable physicochemical properties, the role of HMSPs serving as vehicles for the controlled delivery of DOX into cancer cells has been investigated. Drug release profiles are shown to be pH-responsive with up to 83% DOX release in acidic environments (pH 4.0 and 5.0), whereas low DOX (18%) release occurs at neutral pH (pH 7.4) within 48 h, indicating minimal premature drug release. Moreover, intracellular tracking experiments reveal that DOX-loaded HMSPs could efficiently be taken up by KB cells and exhibit potent anti-proliferation and inhibitory effects against KB cells, as compared to free DOX. Importantly, the DOX-loaded HMSPs show limited cytotoxicity against normal HEK 293 cells with 70% retained viability after incubation at a high concentration of 5.0 μg mL−1, which further demonstrated the potential of microwave-driven HMSPs as desirable drug delivery vehicles.
Co-reporter:Fang Wang, Yuting Zhang, Peng Yang, Sha Jin, Meng Yu, Jia Guo and Changchun Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 17) pp:NaN2582-2582
Publication Date(Web):2013/12/11
DOI:10.1039/C3TB21359E
Functional polymeric microgels have great potential for biomedical applications owing to the outstanding advantages of their well-defined structures and tunable surface properties. However, traditional polymerization methods lack the efficient techniques needed for the fabrication of polymeric microgels. Herein, we have developed a novel technique, reflux-precipitation polymerization, for the preparation of a new type of monodisperse poly(ethylene glycol methacrylate phosphate) (PEGMP) microgel with a well-defined spherical structure and abundant phosphate groups. Furthermore, we have extended this technique to fabricate various monodisperse microgels baring different functional groups, including crosslinked PVIM, PHEMA and PVPBA microgels, as well as non-crosslinked poly(AAm-co-MAA) nanohydrogels, which could serve as promising candidates for specific protein enrichment and drug delivery systems. The morphologies and particle size distributions of the microgels were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), whereas the surface properties were measured via a zeta potential test. In addition, the use of the PEGMP microgels for the identification of phosphoproteins in both a protein mixture and drinking milk was investigated, and demonstrated high selectivity towards phosphoproteins.
Co-reporter:Peng Yang, Jing Ding, Jia Guo, Weibin Shi, Jack J. Hu and Changchun Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 4) pp:NaN551-551
Publication Date(Web):2012/11/06
DOI:10.1039/C2TB00059H
We present a novel self-templating strategy for directly fabricating monodisperse hollow polymer microspheres (HPMs) from vinyl-containing organosilica microspheres (VOMs) through a polymer-backbone-transition method (PBTM). The VOMs play the roles of both templates and precursors in the new shells. The uniform HPMs with varying sizes from 320 nm to 1.6 μm could be obtained by controlling the diameter of the VOMs. Depending on the progress of outer-to-inner shell formation, the range of shell thickness is broadly tunable from 15 nm to 290 nm. Theoretically, through introduction of a suitable vinyl monomer in the shell-formation step, a variety of double-shell hollow polymer microspheres (ds-HPMs) could be fabricated based on this strategy. We then synthesize ds-HPMs by copolymerization of VOMs with N-isopropyl acrylamide (NIPAM) in order to improve the dispersion stability of HPMs in water and provide better oscillation and compressibility. In vitro and in vivo experimental results showed that the ds-HPMs possessed excellent echoing characteristics which could be applied as ultrasound contrast agents for the real-time guidance during the surgical process.
Co-reporter:Dian Li, Yuting Zhang, Sha Jin, Jia Guo, Haifeng Gao and Changchun Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 32) pp:NaN5194-5194
Publication Date(Web):2014/06/12
DOI:10.1039/C4TB00756E
Intelligent nanomaterials that are able to respond to environmental stimuli for sequential release of multiple payloads are highly desirable in applications of drug delivery systems. In this study, a core/shell-structured nanocarrier with an acid-dissolvable magnetic supraparticle (MSP) as core and a redox-degradable poly(methylacrylic acid-co-N,N-bis(acryloyl)cystamine) (P(MAA-Cy)) as shell was prepared using the distillation-precipitation polymerization technique, in which the magnetic core and the polymer shell were loaded with different guest molecules. Under physiological conditions similar to the cytoplasm of tumour cells, this MSP@P(MAA-Cy) microsphere showed a sequential degradation profile of the shell and the core. With dyes of fluorescein isothiocyanate (FITC) loaded in the core and rhodamine in the shell, the produced MSP-FITC@P(MAA-Cy)-Rho microspheres were applied in HeLa cell and HEK 293T cell cultures, showing selective degradation of the microspheres in HeLa cells to release the rhodamine and FITC dyes in sequence. When two anticancer drugs, i.e., paclitaxel (TXL) and doxorubicin (DOX), were loaded separately into the core and the shell domains of the microspheres, the experimental results showed that the MSP-TXL@P(MAA-Cy)-DOX nanodrug exhibited better inhibitive efficacy than the free drugs under the same dosing level, demonstrating the great potential of this stimuli-sensitive drug delivery system for programmed and stimuli-responsive drug release characteristics.
Co-reporter:Dong Yang, Feng Yang, Jianhua Hu, Jiang Long, Changchun Wang, Deliang Fu and Quanxing Ni
Chemical Communications 2009(Issue 29) pp:
Publication Date(Web):
DOI:10.1039/B908012K
Co-reporter:Dian Li, Yuting Zhang, Meng Yu, Qiao An, Jia Guo, Jennifer Q. Lu and Changchun Wang
Chemical Communications 2015 - vol. 51(Issue 10) pp:NaN1910-1910
Publication Date(Web):2014/12/11
DOI:10.1039/C4CC07985J
Porous magnetic supraparticles (p-MSPs) with surface area up to 285.4 m2 g−1 have been fabricated by a one-step etching method, which is 4 times greater than the unetched counterpart. They exhibit significantly better biodegradability than their counterpart in both mimicked physiological buffer solution and the cellular environment of HeLa cells.
Co-reporter:Ying Zhang, Meng Yu, Cheng Zhang, Yali Wang, Yi Di, Changchun Wang and Haojie Lu
Chemical Communications 2015 - vol. 51(Issue 27) pp:NaN5985-5985
Publication Date(Web):2015/02/13
DOI:10.1039/C4CC10285A
A novel method based on the conjunction of aldehydes from oxidized glycopeptides to aniline groups on magnetic nanoparticles via nonreductive amination is reported for the highly selective enrichment of N-glycopeptides. For the first time, a nonreductive amination reaction has been introduced into N-glycoproteome extraction, and correspondingly a new type of aniline-functionalized nanoparticle has been designed and synthesized.
Co-reporter:Ju-Mei Li, Chuan Wei, Wan-Fu Ma, Qiao An, Jia Guo, Jun Hu and Chang-Chun Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 24) pp:
Publication Date(Web):
DOI:10.1039/C2JM30702B
Co-reporter:Wan-Fu Ma, Lu-Lu Li, Ying Zhang, Qiao An, Li-Jun You, Ju-Mei Li, Yu-Ting Zhang, Shuai Xu, Meng Yu, Jia Guo, Hao-Jie Lu and Chang-Chun Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 45) pp:NaN23988-23988
Publication Date(Web):2012/10/01
DOI:10.1039/C2JM35196J
Selective enrichment of glycopeptides from complicated biological samples is essential for MS-based glycoproteomics, but still remains a great challenge. In this study, we report an unprecedented ligand-free strategy for the selective enrichment of glycopeptides by simply utilizing the multivalent interaction between glycopeptides and silver nanoparticles (Ag-NPs) coated magnetic nanoarchitectures. The composite microspheres were deliberately designed to be constructed with a high-magnetic-response magnetic colloid nanocrystal cluster (MCNC) core, a poly(methacrylic acid) (PMAA) interim layer and a Ag-NPs functional shell with high coverage. Taking advantage of the reversible interaction of glycans with Ag-NPs and the high magnetic susceptibility of the magnetite core, the MCNC@PMAA@Ag-NPs microspheres possess remarkable selectivity for glycopeptides even at a low molar ratio of glycopeptides/non-glycopeptides (1:100) with a very rapid enrichment speed (only 1 min needed) and a simple operation procedure using magnetic separation. Applying this approach, we identified 127 unique glycopeptides mapped to 51 different glycoproteins from only 1 μL rat serum samples. These results clearly demonstrated that the MCNC@PMAA@Ag-NPs have great potential for purifying and identifying the low-abundant glycopeptides in complex biological samples.
Co-reporter:Dong Yang, Guiquan Guo, Jianhua Hu, Changchun Wang and Donglin Jiang
Journal of Materials Chemistry A 2008 - vol. 18(Issue 3) pp:NaN354-354
Publication Date(Web):2007/11/22
DOI:10.1039/B713467C
Multi-walled carbon nanotubes (MWNTs) bearing hydroxyl groups (MWNTols) on the exterior surface have been synthesized by an alkaline-mediated hydrothermal treatment of MWNTs under autogenous pressure at 180 °C. X-Ray photoelectron spectroscopy shows that the content of hydroxyl groups increases with the concentration of sodium hydroxide utilized. FT-IR spectroscopy shows that hemiketals were incorporated into the structure of MWNTols. The prepared MWNTols are highly soluble in polar solvents such as water, methanol, butanone and tetrahydrofuran, to give robust stable black solutions. Transmission electron microscopy reveals that the diameter, length and morphology of MWNTs are well retained in MWNTols. MWNTols are redox active on their exterior surface, where hydroxyl groups, upon reaction with Ce(IV) ions, transform to radical species and initiate polymerization of N-isopropylacrylamide (NIPAM).
Co-reporter:Dian Li, Luyan Sun, Yuting Zhang, Meng Yu, Jia Guo and Changchun Wang
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 3) pp:
Publication Date(Web):
DOI:10.1039/C6QM00049E
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