Co-reporter:Kaimin Chen;Fenglin Hu;Hongchen Gu
Journal of Materials Chemistry B 2017 vol. 5(Issue 3) pp:435-443
Publication Date(Web):2017/01/18
DOI:10.1039/C6TB02817A
Controlled protein adsorption and release without deformation and loss of activity under mild conditions is an essential issue for biological carriers. A spherical mixed charged silica brush (MCB), which could tune protein adsorption, has been prepared by introducing zwitterionic carboxybetaine copolymer onto the surface of silica nanoparticles for the first time. The simple surface-initiated reversible addition–fragmentation chain transfer polymerization (SI-RAFT) was applied to synthesize the MCB precursor – poly(2-(dimethylamino)ethyl methacrylate) modified silica nanoparticles (SiO2@PDMAEMA). Then, the end group in PDMAEMA was quaternized with propiolactone to obtain poly(DMAEMA-co-carboxybetaine methacrylate) modified silica nanoparticles (SiO2@poly(DMAEMA-co-CBMA)), which was denoted as MCB. In comparison, fully quaternized MCB (SiO2@PCBMA) was also prepared by a one-step strategy. Physicochemical behaviours of MCB in solution were systematically studied. The zwitterionic CBMA component endows the MCB with tunable adsorption towards both acidic and basic proteins through simple adjustment of the DMAEMA to CBMA ratio under mild conditions. This study may have great potential applications in the biomedical field, including tunable drug loading and releasing, and immobilized enzymes, etc.
Co-reporter:Ye Lin;Chaoqing Dong;Fengwen Cao;Liqin Xiong;Hongchen Gu
RSC Advances (2011-Present) 2017 vol. 7(Issue 88) pp:55957-55965
Publication Date(Web):2017/12/07
DOI:10.1039/C7RA12164D
A strong and stable fluorescent signal is the crux for the ultrasensitive biodetection technology, conjugated polymer nanoparticles (CPNs) as new fluorescence labels have attracted more and more attention for their excellent optical properties. However, a systematic understanding of the size-dependent optical properties of CPNs with diameters from the nano to submicron ranges is lacking, which is the most important issue when choosing label materials. Hence, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)] (PFBT) nanoparticles with sizes from 50 nm to 200 nm were synthesized and studied. It was demonstrated that the spectroscopic and fluorescent properties are similar for CPNs with different sizes. The relationship between single-particle brightness and diameter was investigated via fluorescence spectrometry and fluorescence correlation spectroscopy (FCS), and the results presented that the single-particle brightness increased quadratically with the increase of the diameter of CPNs. This research may provide valuable support to further application of CPNs in biological diagnostics.
Co-reporter:Shanshan Wang;Zhonghui Liu;Carmen Bartic
Journal of Nanoparticle Research 2016 Volume 18( Issue 8) pp:
Publication Date(Web):2016 August
DOI:10.1007/s11051-016-3546-3
Surface-enhanced Raman scattering (SERS) tags show ultrasensitivity and multiplexing abilities due to strong and characteristic Raman signals and therefore can be utilized as optical labeling agents similar to fluorescent dyes and quantum dots for biosensing and bioimaging. However, SERS tags have the difficulty to realize quantitative analysis due to the uniformity and reproducibility issue. In this work, we have reported on a new type of SERS tag called Au rod-in-shell (RIS) gap-enhanced Raman tag (GERT). With the high-resolution transmission electron microscopy (TEM) and optical absorbance measurements, we have demonstrated the subnanometer sized gap junctions inside the RIS GERTs. SERS measurements and FDTD calculations show that the core–shell subnanometer gap geometry in the RIS GERTs not only generates strong SERS hot spots but also isolates SERS hot spots by Au shells to avoid the influence when the particle aggregates form, therefore showing better SERS uniformity and stronger SERS intensity than normal Au nanorods. Those RIS NPs exhibit great potential as the labeling agents for SERS-based bioimaging and biosensing applications.
Co-reporter:Zhenyuan Qu, Hong Xu, and Hongchen Gu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 27) pp:14537
Publication Date(Web):June 12, 2015
DOI:10.1021/acsami.5b02912
Poly((meth)acrylic acid) (P(M)AA) brushes possess a number of distinctive properties that are particularly attractive for biomedical applications. This minireview summarizes recent advances in the synthesis and biomedical applications of P(M)AA brushes and brushes containing P(M)AA segments. First, we review different surface-initiated polymerization (SIP) methods, with a focus on recent progress in the surface-initiated controlled/living radical polymerization (SI-CLRP) techniques used to generate P(M)AA brushes with a tailored structure. Next, we discuss biomolecule immobilization methods for P(M)AA brushes, including physical adsorption, covalent binding, and affinity interactions. Finally, typical biomedical applications of P(M)AA brushes are reviewed, and their performance is discussed based on their unique properties. We conclude that P(M)AA brushes are promising biomaterials, and more potential biomedical applications are expected to emerge with the further development of synthetic techniques and increased understanding of their interactions with biological systems.Keywords: biomedical application; poly(acrylic acid) brushes; poly(methacrylic acid) brushes; protein immobilization; surface-initiated polymerization;
Co-reporter:Peirui Wang, Ping Xu, Pingping Wang, Lingling Deng, Hongchen Gu, and Hong Xu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 44) pp:24390
Publication Date(Web):October 30, 2015
DOI:10.1021/acsami.5b07733
To achieve higher protein immobilization and bioactivity, as well as automatic manipulation, we prepared a new type of biocarrier based on the brushed beads-on-beads structure. Many poly(acrylic acid) (PAA) brushed nanoparticles were packed onto the surface of amino-functionalized magnetic particles through an efficient carbodiimide-assisted coupling reaction to attain a hierarchical structure, a unique three-dimensional (3D) space and automatic manipulation characteristics. The proposed biocarrier was evaluated in the recognition capability of the immunocomplex and showed a 6.7-fold increase compared with control beads with a hard surface. The results of this study suggest promising applications in targeted capture and high-performance biodetection processes.Keywords: automatic manipulation; brushed beads-on-beads; fluidlike interface; higher protein immobilization; immunocomplex; recognition capability
Co-reporter:Fenglin Hu, Kaimin Chen, Hong Xu, Hongchen Gu
Colloids and Surfaces B: Biointerfaces 2015 Volume 126() pp:251-256
Publication Date(Web):1 February 2015
DOI:10.1016/j.colsurfb.2014.12.036
•A novel functional zwitterion coated silica nanoparticles (SiO2-ZWS) was synthesized.•The SiO2-ZWS owns excellent antifouling property.•The interaction between SiO2-ZWS and proteins were investigated deeply.A new functional nanoparticle, consisting of a silica core onto which short-chain zwitterions are chemically connected, was successfully prepared and showed excellent antifouling performance to protein solutions. These nanoparticles (NPs) own excellent stability even in 1 M NaCl solutions for at least 48 h. The interaction between these “zwitterated” NPs and proteins were investigated by dynamic light scattering (DLS), turbidimetric titration, and isothermal titration calorimetry (ITC). The results demonstrated that the zwitterated NPs had antifouling property both in single protein solutions and serum (fetal bovine serum, FBS). The zwitterated NPs also own abundant functional groups which could conjugate with biomolecules for future applications in therapeutic and diagnostic field.
Co-reporter:Zhenyuan Qu, Hong Xu, Ping Xu, Kaimin Chen, Rong Mu, Jianping Fu, and Hongchen Gu
Analytical Chemistry 2014 Volume 86(Issue 19) pp:9367
Publication Date(Web):September 8, 2014
DOI:10.1021/ac502522b
Improving the detection sensitivity of enzyme-linked immunosorbent assay (ELISA) is of utmost importance for meeting the demand of early disease diagnosis. Herein we report an ultrasensitive ELISA system using horseradish peroxidase (HRP)-loaded nanospherical poly(acrylic acid) brushes (SPAABs) as labels. HRP was covalently immobilized in SPAABs with high capacity and activity via an efficient “chemical conjugation after electrostatic entrapment” (CCEE) process, thus endowing SPAABs with high amplification capability as labels. The periphery of SPAAB-HRP was further utilized to bind a layer of antibody with high density for efficient capture of analytes owing to the three-dimensional architecture of SPAABs. Using human chorionic gonadotrophin (hCG) as a model analyte, the SPAAB-amplified system drastically boosted the detection limit of ELISA to 0.012 mIU mL–1, a 267-fold improvement as compared to conventional ELISA systems.
Co-reporter:Zhenyuan Qu, Kaimin Chen, Hongchen Gu, and Hong Xu
Bioconjugate Chemistry 2014 Volume 25(Issue 2) pp:370
Publication Date(Web):December 28, 2013
DOI:10.1021/bc400530s
Polymeric brushes have emerged as a novel 3D material platform that provides great amounts of binding sites for biomolecules. This paper investigates the covalent immobilization mechanism of protein by spherical poly(acrylic acid) brushes (SPAABs) in the widely adopted N-hydroxysuccinimide/N-(3-dimethyl-aminopropyl)-N′-ethylcarbodiimide hydrochloride (NHS/EDC) process. It was discovered that electrostatic interaction plays a crucial role in the covalent immobilization of protein. Due to the existence of 3D architecture and “Donnan effect”, SPAABs exhibit quite different immobilization kinetics in comparison with conventional 2D materials. Under conditions favorable to electrostatic interaction, the effect of “electrostatic interaction induced covalent binding” was observed as a result of competitive immobilization by physical adsorption and chemical binding. On the basis of the mechanism study, a new “chemical conjugation after electrostatic entrapment” (CCEE) method was developed which set the chemical and physical immobilization process apart. A more effective and well-defined covalent immobilization was achieved. And the binding capacity can be tuned in a wide range (0–4.2 mg protein/mg SPAABs) with a high level of control.
Co-reporter:Shanshan Wang, Hong Xu and Jian Ye
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 24) pp:12275-12281
Publication Date(Web):28 Apr 2014
DOI:10.1039/C4CP00902A
The plasmonic gold nanoparticles are promising candidates for photothermal therapy (PTT) application. The optical properties of various gold nanoparticles have been widely investigated for PTT application in the first near-infrared (NIR) window (650–950 nm). However, few studies have been reported on the nanoparticles employed in the second NIR window (1000–1350 nm) where light penetrates deeper through the tissue. Recently, a new type of plasmonic rod-in-shell (RIS) nanoparticle that can be optically responsive in the second NIR window has been reported (ACS Nano, 2013, 7, 5330). In this article, we employed an extensive numerical exploration of the optical absorption properties of the RIS particles by tuning their dimensional parameters including the core length, gap size and shell thickness. A number of favorable optical properties of the RIS nanoparticles potentially for the better PTT effect have been observed including: (1) the strong and highly tunable optical absorption in the second NIR window with a particle size less than 100 nm; (2) a larger absorption cross-section both in the first and second NIR windows over a nanorod with the same gold mass; and (3) orientation-insensitive light absorption by particles in the first NIR window due to the overlapping of the longitudinal and transverse modes. These unique optical properties imply that the RIS nanoparticles could become promising candidates for the PTT application in the first and second NIR windows.
Co-reporter:Xiaoyan Dai, Hong Xu, Xin Zhang, Wei Zhu, Hongchen Gu, Meng Wei
Materials Science and Engineering: C 2014 Volume 34() pp:422-428
Publication Date(Web):1 January 2014
DOI:10.1016/j.msec.2013.09.040
•We determined KA of streptavidin magnetic particles and biotinylated antibody.•Streptavidin density below 83 μg/mg of particle had no influence on KA.•Performance of streptavidin magnetic particles in immunoassay was studied.Streptavidin-coupled magnetic particles (SAMPs) usually serve as a separation tool in immunoassays to specifically recognize and capture biotinylated protein. Determining the affinity constant (KA) of SAMPs and biotinylated proteins and further evaluating the performance of SAMPs as a solid-phase carrier are of great importance. Towards this goal, we present a simple method to detect the KA of SAMPs and a biotinylated antibody (Ab). A combined equilibrium equation derived from fluorescence labeling experiments was employed to evaluate the binding capacity between SAMPs and a biotinylated antibody. The main experimental conditions were optimized, and the KA of SAMPs and a biotinylated antibody was determined to be 3.64 ± 0.31 × 107 M− 1 with a coefficient of variation (CV) of 8.38%. The initial effective biotinylated antibody binding sites of as-synthesized SAMPs were found to be 132 pmol/mg SAMPs. In addition, the KA of Ab towards SAMPs with four different streptavidin coating densities (16–83 μg/mg MPs) was studied, and the results showed no significant difference for the KA among these four SAMPs. This suggests that the binding activity of SAMPs with Ab would not be affected by the streptavidin coupling density at least below 83 μg/mg MPs. However, when the four SAMPs were used as the capture reagent in sandwich immunoassays, the SAMPs with streptavidin coating density of 83 μg/mg MPs had a lower affinity than the other three SAMPs with less streptavidin coating density.
Co-reporter:Ye-fei Wang 王叶菲;Xin Zhang 张 欣;Ping Xu 徐 平
Journal of Shanghai Jiaotong University (Science) 2014 Volume 19( Issue 5) pp:538-543
Publication Date(Web):2014 October
DOI:10.1007/s12204-014-1537-z
Well-defined raspberry-like magnetic microbeads (RMMBs) as immunoassay solid carriers were prepared by chemical covalent binding between Fe3O4 magnetic microspheres and SiO2 nanoparticles. These RMMBs were not as agglomerative as nano-sized magnetie particles (< 200 nm), which was an advangtage for high efficient magnetic separation. When compared to Fe3O4@SiO2 core-shell magnetic microbeads (CMMBs) with smooth surface, RMMBs exhibited stronger capacity to bind biomolecules. Limit of blank (LoB) and limit of detection (LoD) of HBsAg detection using RMMBs as carriers via chemiluminiscence immunoassay (CLIA) were 0.472 and 1.022 μg/L, respectively, showing a notable improvement compared with CMMBs whose LoB and LoD were 1.017 and 1.988 μg/L, respectively. All these indicated a great potential of RMMBs in immunoassay application.
Co-reporter:Yilong Wang, Fangyingkai Wang, Bingdi Chen, Hong Xu and Donglu Shi
Chemical Communications 2011 vol. 47(Issue 37) pp:10350-10352
Publication Date(Web):19 Aug 2011
DOI:10.1039/C1CC13463A
Yolk-shell composites with an Fe3O4/silica hybrid shell and a polymer core are prepared via a facile one-pot and self-template process. Thicknesses of the inorganic shell and interior space of the composites are well controlled by tuning the ternary phase separations.
Co-reporter:Xian’an Zhang, Weifeng Lin, Shengfu Chen, Hong Xu, and Hongchen Gu
Langmuir 2011 Volume 27(Issue 22) pp:13669-13674
Publication Date(Web):October 4, 2011
DOI:10.1021/la202566d
To overcome major challenges of non-specific protein adsorption on nanoparticles for nanosensing and nanodiagnosis, an efficient method for robust chemical modification was developed to achieve excellent specific biorecognition and long-term stability in complex biomedia. This method is demonstrated by a highly specific and sensitive immunoassay (IA), using superparamagnetic nanospheres (NSs) with high magnetite content. The non-specific protein adsorption on the NSs was suppressed dramatically when modified with dual functional poly(carboxybetaine methacrylate) (polyCBMA) via surface-initiated atom transfer radical polymerization (SI-ATRP) and chemically grafted with antibodies of the β subunit of human chorionic gonadotrop (anti-β-hCG). The response to hCG of IA NSs with polyCBMA coatings was highly consistent in either phosphate-buffered saline (PBS) or 50% fetal bovine serum (FBS), which is far less variable than the response of the IA NSs without polyCBMA coatings. After all, a very robust platform for IA NSs with excellent specific biorecognition was obtained. It is expected that this method for nanoparticle modification could be widely used in ultrasensitive nanosensing and nanodiagnosis in the future.
Co-reporter:Yawen Xu;Hongchen Gu
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 11) pp:2284-2293
Publication Date(Web):
DOI:10.1002/pola.23984
Abstract
The synthesis of functional magnetic polymer latexes (MPLs) with epoxy groups introduced via a modified miniemulsion polymerization route was described. The epoxy group content on the surface could be controlled by seed emulsion followed and characterized by FTIR and zeta potential measurements. We also developed a novel approach to achieve manipulation of the morphology of the MPLs based on kinetic control of the polymerization system. MPLs with different morphologies were obtained ranging from core–shell microstructures, dispersed microstructures to asymmetric microstructure, which were characterized by TEM, DLS, and TGA. The mechanisms of the contribution of kinetic factors such as polymerization rate, reaction time, and temperature contributing to the formation of the different morphologies were also investigated. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2284–2293, 2010
Co-reporter:Shaoyan Yuan;Hongchen Gu
Journal of Applied Polymer Science 2008 Volume 110( Issue 4) pp:1955-1960
Publication Date(Web):
DOI:10.1002/app.27718
Abstract
Polypropylene (PP) and nano-calcium carbonate (CaCO3) composites were prepared by melt mixing in a corotating twin-screw extruder. Transmission electron microscopy study and particle size analysis revealed the dispersion and the size distribution of CaCO3 in PP. With the increase of loading of filler, CaCO3 nanoparticles densely aggregated together and the dispersion of filler became bad. The fractal dimensions of the composites were determined using fractal concept. The fractal dimensions of D and Dk described the irregularities of the shape of an object and the distributions of particle populations, respectively. The D and Dk values were influenced by the content of filler, i.e., the D values increased, and the Dk values decreased with the increase of loading of filler. When the loading of filler was low, the values of D and Dk of PP composites differ slightly than the counterparts of PP/PP-g-MA (50 wt %) blend. For 20 wt %, they were almost identical. This fact showed that the fractal dimension was correlated with the dispersion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Shanshan Wang, Hong Xu and Jian Ye
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 24) pp:NaN12281-12281
Publication Date(Web):2014/04/28
DOI:10.1039/C4CP00902A
The plasmonic gold nanoparticles are promising candidates for photothermal therapy (PTT) application. The optical properties of various gold nanoparticles have been widely investigated for PTT application in the first near-infrared (NIR) window (650–950 nm). However, few studies have been reported on the nanoparticles employed in the second NIR window (1000–1350 nm) where light penetrates deeper through the tissue. Recently, a new type of plasmonic rod-in-shell (RIS) nanoparticle that can be optically responsive in the second NIR window has been reported (ACS Nano, 2013, 7, 5330). In this article, we employed an extensive numerical exploration of the optical absorption properties of the RIS particles by tuning their dimensional parameters including the core length, gap size and shell thickness. A number of favorable optical properties of the RIS nanoparticles potentially for the better PTT effect have been observed including: (1) the strong and highly tunable optical absorption in the second NIR window with a particle size less than 100 nm; (2) a larger absorption cross-section both in the first and second NIR windows over a nanorod with the same gold mass; and (3) orientation-insensitive light absorption by particles in the first NIR window due to the overlapping of the longitudinal and transverse modes. These unique optical properties imply that the RIS nanoparticles could become promising candidates for the PTT application in the first and second NIR windows.
Co-reporter:Yilong Wang, Fangyingkai Wang, Bingdi Chen, Hong Xu and Donglu Shi
Chemical Communications 2011 - vol. 47(Issue 37) pp:NaN10352-10352
Publication Date(Web):2011/08/19
DOI:10.1039/C1CC13463A
Yolk-shell composites with an Fe3O4/silica hybrid shell and a polymer core are prepared via a facile one-pot and self-template process. Thicknesses of the inorganic shell and interior space of the composites are well controlled by tuning the ternary phase separations.
Co-reporter:Kaimin Chen, Fenglin Hu, Hongchen Gu and Hong Xu
Journal of Materials Chemistry A 2017 - vol. 5(Issue 3) pp:NaN443-443
Publication Date(Web):2016/12/02
DOI:10.1039/C6TB02817A
Controlled protein adsorption and release without deformation and loss of activity under mild conditions is an essential issue for biological carriers. A spherical mixed charged silica brush (MCB), which could tune protein adsorption, has been prepared by introducing zwitterionic carboxybetaine copolymer onto the surface of silica nanoparticles for the first time. The simple surface-initiated reversible addition–fragmentation chain transfer polymerization (SI-RAFT) was applied to synthesize the MCB precursor – poly(2-(dimethylamino)ethyl methacrylate) modified silica nanoparticles (SiO2@PDMAEMA). Then, the end group in PDMAEMA was quaternized with propiolactone to obtain poly(DMAEMA-co-carboxybetaine methacrylate) modified silica nanoparticles (SiO2@poly(DMAEMA-co-CBMA)), which was denoted as MCB. In comparison, fully quaternized MCB (SiO2@PCBMA) was also prepared by a one-step strategy. Physicochemical behaviours of MCB in solution were systematically studied. The zwitterionic CBMA component endows the MCB with tunable adsorption towards both acidic and basic proteins through simple adjustment of the DMAEMA to CBMA ratio under mild conditions. This study may have great potential applications in the biomedical field, including tunable drug loading and releasing, and immobilized enzymes, etc.
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