•Boronic acid-functionalized silica was prepared.•The adsorption and desorption equilibrium can be completed within a short time.•The adsorption capacity was larger than that of other materials.•The material was successfully applied to enrich intracellular nucleosides.Boronic acid modified materials have been widely used to adsorb nucleosides, but their adsorption capacities require further improvement. Most cis-diol containing biomolecules are in very low abundance along with interfering components in real samples, and need to be enriched specially. In this study, we synthesize a kind of silica absorbent modified with boronic acid derivative, using amorphous silica as raw material and obtaining high adsorption capacity for adenosine. In addition, the adsorption equilibrium can be completed within 10 s and 1 min for the desorption. Finally, the material was successfully applied to enrich nucleosides from cells and the spiked recoveries were found between 82.21% and 118.9%. The results showed that the prepared adsorbent has potential to effectively enrich cis-diol substances from cell samples.
Analytical and Bioanalytical Chemistry 2017 Volume 409( Issue 12) pp:3127-3133
Publication Date(Web):2017 May
DOI:10.1007/s00216-017-0253-6
Solid-phase microextraction with polysulfone and molecularly imprinted polymers as coating on nickel foam were used to adsorb and enrich floxacin drugs. The preparation method is simple and reproducible to obtain the materials with controlled thickness. After evaluation by scanning electron microscope and various adsorption experiments, the materials were used to adsorb analytes in water samples and biological samples. Coupling with chromatographic analysis, the method recoveries are satisfactory with 90.0–104.8% and 79.31–107.1% for water and biological samples. The method repeatability by intra- and interday experiments shows that the RSD values for water and biological samples were 1.0–9.9% and 1.7–10.3%, with the quantitative limits of three floxacin drugs as 3.0–6.2 μg L−1.
A two-photon ratiometric fluorescent probe (Mito-N) has been developed for monitoring mitochondrial nitric oxide (NO) in vivo. Mito-N exhibited excellent selectivity and sensitivity toward NO among various ROS/RNS. The successful two-photon imaging of mitochondrial NO proved that Mito-N is a powerful noninvasive imaging tool in living systems.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 Volume 180(Volume 180) pp:
Publication Date(Web):5 June 2017
DOI:10.1016/j.saa.2017.03.017
•A ratiometric fluorescent sensor for fructose was presented.•It consisted of 10-hydroxybenzo[h]quinoline (HBQ) and boronic acid.•The principle relied on competition between fructose and HBQ for boronic acid.•This sensor was simple, inexpensive, stable and sensitive.A simple ratiometric fluorescent sensor for fructose was presented. It consisted of 10-hydroxybenzo[h]quinoline (HBQ) which showed emission at 572 nm and 3-pyridylboronic acid (PDBA) whose complex with HBQ gave emission at 500 nm. The reaction of fructose with PDBA inhibited the complexation of HBQ with PDBA, resulting in the change of dual-emission intensity ratio. The sensor well quantified fructose in the range of 0.015–2.5 mM with detection limit of 0.005 mM. Besides, this sensor exhibited excellent selectivity and was successfully applied to fructose detection in food. This work provides a simple ratiometric sensing platform for sensitive and selective detection of fructose.Download high-res image (100KB)Download full-size image
Boronate affinity materials have been widely used for selective extraction of cis-diols, but their extraction efficiency is far from adequate. We have synthesized porous magnetic polysulfone capsules containing mesoporous silica nanoparticles of type SBA-15 that were functionalized with boronic acid derivative. The spheres were then coated with the cationic surfactant hexadecyltrimethylammonium bromide which binds to the surface due to hydrophobic and ionic interactions. The surfactant coated sorbents possess an enrichment capability and selectivity that is distinctly better than that of non-coated sorbents. The limits of detection for four nucleosides extracted from aqueous sample solutions are in the range from 1.13 to 1.74 ng mL−1. The selective enrichment of trace quantities of nucleosides is illustrated by quantifying nucleosides after extraction from HepG2 cells.
The authors describe a filter paper modified with mesoporous silica that carries phenylboronic acid on its surface. The material possesses the advantages of the flexibility of filter paper and the large surface of mesoporous silica. This makes it an excellent sorbent for the enrichment of trace quantities of nucleosides. The limits of detection (in HPLC analysis with UV detection) are 2.0–11.1 μg L−1 and the limits of quantification are 6.8–37.1 μg L−1 with good precision (RSD < 6.4%). Compared to plain filter paper and nonporous silica-coated filter paper, the material exhibits enhanced efficiency and a 4.5-fold improved capacity. The potential applications are demonstrated by preconcentrating nucleosides from HepG2 cells which are a representative complex sample. The method was also used to study the effect of 30-nm gold nanoparticle on cellular metabolism.
Co-reporter:Jianjian Zhang, Chuwen Li, Rui Zhang, Fengyuan Zhang, Wei Liu, Xiaoyan Liu, Simon Ming-Yuen Lee and Haixia Zhang
Chemical Communications 2016 vol. 52(Issue 13) pp:2679-2682
Publication Date(Web):05 Jan 2016
DOI:10.1039/C5CC09976E
A novel near-infrared (NIR), turn-on fluorescence probe CyR containing a phosphinate group as a recognizing moiety for the selective detection of O2˙− with a low limit of detection (LOD, 9.9 nM) was developed. CyR has good cell-membrane permeability, intracellular stability, and low cytotoxicity. In addition, we successfully applied the CyR to visualize O2˙− in live zebrafish, mouse and, for the first time, in mouse liver.
Co-reporter:Ting Cheng;Shuqiang Zhu;Bin Zhu;Xiaoyan Liu ;Haixia Zhang
Journal of Separation Science 2016 Volume 39( Issue 7) pp:1347-1356
Publication Date(Web):
DOI:10.1002/jssc.201500968
The nucleoside or modified nucleoside level in biological fluids reflects the pathological or physiological state of the body. Boronate affinity absorbents are widely used to selectively extract nucleosides from complex samples. In this work, a novel functionalized absorbent was synthesized by attaching 4-mercaptophenylboronic acid to gold nanoparticles on modified attapulgite. The surface of the attapulgite was modified by poly(acryloyloxyethyltrimethyl ammonium chloride) by atom transfer radical polymerization, creating many polymer brushes on the surface. The resultant material exhibited superior binding capacity (30.83 mg/g) for adenosine and was able to capture cis-diol nucleosides from 1000-fold interferences. Finally, to demonstrate its potential for biomolecule extraction, this boronate affinity material was used to preconcentrate nucleosides from human urine and plasma.
A two-photon (TP) fluorescence imaging probe (Z1) was designed to detect biothiols through a photoinduced electron transfer pathway utilizing N-butyl-naphthalimide as the fluorophore and 2,4-dinitrobenzene-sulfonyl as the responsive group, which were linked together by piperazine. The synthesized Z1 displayed high selectivity to biothiols, significant fluorescence off–on properties, and a marked two-photon absorption cross section (δ = 110 GM). Moreover, Z1 showed good biocompatibility and insensitivity toward changes in the biologically relevant pH range (7.2–8.4), which enabled the utilization of Z1 to monitor biothiol levels not only in live cells but also in tissues at depths of 50–250 μm.
Co-reporter:Xinyue Zhu, Hong Gao, Wenyan Zan, Yan Li, Jianjian Zhang, Xiaoyan Liu, Xuan Wei, Fengchao Qi, Xiaojun Yao, Haixia Zhang
Tetrahedron 2016 Volume 72(Issue 16) pp:2048-2056
Publication Date(Web):21 April 2016
DOI:10.1016/j.tet.2016.03.013
It was reported here a devised and synthesized thiol fluorescent probes ortho-Z3, meta-Z3 and para-Z3 based on photoinduced electron transfer (PET) pathway utilizing fluorophore naphthalimide as the electron donor and responsive group maleimide as the electron acceptor. The fluorescence intensity of these probes varied significantly depending on the position of the maleimide toward the naphthalimide fluorophore. Comparing to the meta and para isomers, the ortho isomer displayed the best fluorescence response performances upon addition of thiols. The results indicated that relative position of the electron acceptor played key role in the PET process, and probe ortho-Z3 could detect endogenous biothiols in serum samples and live cells successfully.
Biosensors and Bioelectronics 2016 Volume 83() pp:334-338
Publication Date(Web):15 September 2016
DOI:10.1016/j.bios.2016.04.034
•Two high performance probes were simply synthesized with turn-on response.•The Probe 1 worked best under physiological conditions with high sensitivity.•Excellent biocompatibility facilitated Probe 2 to achieve bioimaging of Au3+.•Both probes displayed rapid response for Au3+ with low detection limit.The 4−N,N-dimethyl-1,8-naphthalimide based fluorescent probes have been explored for selective detection of Au3+. Both probes show a pronounced fluorescence enhancement response to Au3+. Hydroxy is introduced as ligand of Au3+ for Probe 1 and the newly designed Probe 2 contains an alkyne moiety to recognize Au3+ through an irreversible C≡C bond hydrolysis reaction. Probe 1 exhibits higher performance such as faster response, lower detection limit of 0.050 μM and the better responsive effect in 99.5% water system compared with most of probes published. The Probe 2 displays high stability to pH, suitable water solubility, wider linear range (0–100 μM) to Au3+, and live-cells imaging with low cytotoxicity.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2016 Volume 166() pp:31-37
Publication Date(Web):5 September 2016
DOI:10.1016/j.saa.2016.05.004
•A new fluorescence turn-on probe for biothiols was developed.•The probe could selectively detect cysteine at pH 3.5.•The probe responded well to cysteine, glutathione and homocysteine at pH 5.5.•The probe was successfully applied for imaging of thiols in living cells.A new biothiol-selective fluorescent probe 1 based on photoinduced electron transfer (PET) mechanism was designed and synthesized. The UV–Vis absorption and fluorescent emission properties of probe 1 towards various analytes were studied in detail. The probe exhibited a large stokes shift (~ 200 nm) after reacted with biothiols and could selectively detect cysteine (Cys) in dimethyl sulfoxide (DMSO)/H2O solution (9:1, v/v, 10 mM phosphate buffer saline, pH 3.5) over glutathione (GSH), homocysteine (Hcy) and other analytes with a detection limit of 0.117 μM. In addition, probe 1 responded well to GSH, Hcy and Cys in the same above solution with pH 5.5 and got the detection limits of 0.151 μM, 0.128 μM and 0.037 μM, respectively. Probe 1 was of very low cytotoxicity and successfully applied for imaging of thiols in living cells.
•Boronic acid-functionalized attapulgite was prepared.•Ionic liquid (IL) was coated on the material via physical self-assembly process.•IL-coated adsorbent was used for the extraction of nucleosides.•Extraction efficiency of the material increased dramatically after coated with IL.•Enrichment ratios for nucleosides increased by 9- to 282-fold with adding IL.Boronate affinity materials have been widely used for selective capture of cis-diol-containing molecules, but most do not have sufficient extraction efficiency. We have prepared boronic acid-functionalized attapulgite, and then it was coated with imidazolium-based ionic liquid, 1-dodecyl-3-methylimidazolium bromide (C12mimBr), via physical self-assembly process. The extraction efficiency of the material increased dramatically after coated with C12mimBr, and its enrichment ratios for nucleosides increased by 9- to 282-fold. Besides, the C12mimBr-coated adsorbent did not lose selectivity and was able to capture cis-diols in the presence of a 100-fold excess of interferences. C12mimBr-coated material was applied to selective enrichment of nucleosides from human urine. The limits of detection and the limits of quantification were in the range of 0.06–0.46 ng mL−1 and 0.20–1.53 ng mL−1, respectively. Reproducibility of the method was determined with relative standard deviations≤9.9%. The recoveries of the target nucleosides from spiked human urine were in the range of 87.8–109.6%. In our preception, self-assembly ionic liquid layer can serve as a promising alternative to improve the extraction efficiency of boronate affinity materials.
Materials Science and Engineering: C 2016 Volume 59() pp:258-264
Publication Date(Web):1 February 2016
DOI:10.1016/j.msec.2015.10.022
•Dual-sensitive nanocarrier based on pH and glutathione was fabricated.•Ultra small Au NPs acting as gatekeepers to achieve the controlled release•The drug delivery system exhibited less premature release.•The drug delivery system enabled the high growth inhibition toward Tca8113 cells.Mesoporous silica nanoparticles (MSNs) combining gold particles (MSNs–Au) were synthesized as nanocarriers for glutathione (GSH) and pH dual-sensitive intracellular controlled release of the anti-cancer drug doxorubicin (DOX). The MSNs were used as an adsorbent for DOX, and the ultra-small gold nanospheres (Au NPs) partly operated as gatekeepers to control the release of DOX from the pores of MSNs and as the driver of drug release in the presence of GSH due to the association between GSH and Au particles. Under different pH conditions, DOX release changed due to different levels of dissociation between the –SH group on the MSNs and the Au particles. The composition, morphology, and properties of the as-prepared composites were characterized by elemental analysis, fluorescence spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, nitrogen adsorption–desorption, thermal gravimetric and UV–visible spectroscopy. The in vitro release experiments showed that these smart nanocarriers effectively avoided drug leakage in the neutral media. Cytotoxicity and imaging studies also indicated that DOX-loaded Au-MSNs (DOX@MSNs–Au) had a significant inhibitory effect on the growth of Tca8113 cells and sustained the release rate of DOX
The authors describe a colorimetric method for the determination of Hg(II) ions by exploiting the peroxidase-lile activity of few-layered MoS2 nanosheets (MoS2-NSs). These were prepared by sonication-induced exfoliation of bulk MoS2 crystals in aqueous surfactant solution. The MoS2-NSs were found to acts as a peroxidase mimic that is capable of oxidizing the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) to give a blue product with an absorption maximum at 652 nm. The addition of Hg(II) strongly accelerates the kinetics of this reaction. It is shown that the enzyme mimic possesses a high affinity for TMB and a lower pseudo-Michaelis-Menten constant. The stimulating effect of Hg(II) is seriously influenced by the change of surface charge. The use of nanosheets covered with (negatively charged) polystyrene sulfonate results in a decrease in the formation of blue dye, while those covered with (cationic) poly(diallyldimethyl ammonium) ions cause a small increase. Under optimal conditions, the peroxidase-like activity of MoS2-NSs is affected by Hg(II) in the 2.0 to 200 μM concentration range. The method has a detection limit (LOD) of 0.5 μM which is much below the allowed level in cosmetics (1 ppm; ca. 5 μM). The method display excellent sensitivity, selectivity and stability. It was applied to the determination of total mercury in cosmetic samples, and results compared well with results obtained by ICP-AES.
The near-infrared (NIR) fluorescence sensor for rapid, selective, and sensitive detection of cystenine (Cys) is of great importance in both biological and environmental sciences. Herein, we report a specific probe with turn-on fluorescence property, visible color change with naked-eye, and large wavelength shift on UV spectra for highly selective detection of Cys over homocysteine (Hcy) and glutathione (GSH) in both HEPES buffer (10 mM, pH 7.4) and diluted human serum. The probe based on the conjugate addition–cyclization reaction has a low limit of detection to Cys (0.16 μM as NIR fluorescence sensor and 0.13 μM as UV sensor). Kinetic study indicated that the probe has a very rapid response to Cys, owing to the much higher pseudo-first-order reaction constant with Cys (299 M–1 s–1) than with Hcy (1.29 M–1 s–1) or GSH (0.53 M–1 s–1). Upon addition of Cys to a solution of the probe, the color changed from purple to cyan, with the maximum wavelength shifting from 582 to 674 nm in the UV spectrum and a fluorescence emission at 697 nm appearing. It has been successfully applied for determination of Cys in diluted serum and bioimaging of Cys in living cells with low cell toxicity.
Hydrazine has been applied diffusely in most of the chemical industry; however, it is a hazardous environmental pollutant and highly toxic to organisms. Selective, rapid, and sensitive detection of hydrazine thus becomes absolutely necessary in both biological and environmental sciences. Accordingly, fluorescence probes for hydrazine have been paid great attention in recent years. Disclosed here is the near-infrared (NIR) fluorescence probe with a turn-on fluorescent probe CyJ based on the structure–emission property relationships of the NIR dyes containing an acetyl group as the recognizing moiety. This new probe not only can be readily prepared, but also shows excellent sensing properties. First and most important of all, CyJ is highly selective for N2H4 over various anions, cations, and other amino compounds and has a low limit of detection (LOD) of hydrazine (5.4 ppb as fluorescence sensor and 6.1 ppb as UV sensor). Besides, CyJ exhibited a dramatic increase in fluorescence at λmax = 706 nm in the presence of N2H4, and it offers a rapid, colorimetric and vapor sensing detection process for N2H4 in both aqueous solution and diluted human serum. Furthermore, CyJ has good cell-membrane permeability and low cytotoxicity. In addition, we have successfully applied the CyJ to visualize N2H4 in live mouse and, for the first time, in tissues such as the liver, lung, kidney, heart, and spleen.
•Dopamine was modified on stainless steel fiber as MIP fiber support.•The stainless steel fiber was put into a capillary for the synthesis.•Several capillaries were put together in same synthesis solution.•The obtained MIP was evaluated well using different techniques.•The MIP fiber was used to pretreat the milk samples to measure ofloxacin.A kind of new temperature sensitive molecularly imprinted polymer (MIP) with ofloxacin (OFL) as template was prepared for the coating of solid phase microextraction (SPME). Dopamine was self-polymerized on stainless steel fiber (SSF) as the SPME support followed by silanization. Then MIP was synthesized as SPME coating on the modified SSF in a capillary, with N-isopropyl acrylamide as temperature sensitive monomer and methacrylic acid as functional monomer. The synthesis could be well repeated with multiple capillaries putting in the same reaction solution. The obtained MIP fiber was evaluated in detail with different techniques and various adsorption experiments. At last the MIP fiber was used to extract the OFL in milk. Satisfied recoveries between 89.7 and 103.4% were obtained with the limit of quantification (LOQLC) of 0.04 μg mL−1 by the method of SPME coupled with high performance of liquid chromatography (HPLC).Figure optionsDownload full-size imageDownload as PowerPoint slide
European Journal of Organic Chemistry 2015 Volume 2015( Issue 8) pp:1711-1718
Publication Date(Web):
DOI:10.1002/ejoc.201403398
Abstract
With increasing interest in optical in vivo imaging, there is a corresponding increase in demand for near-infrared (NIR) dyes. Such probes can be used, for example, to detect intracellular GSH, which would be helpful for understanding the mechanisms of diseases. In this work, we report a cyanine-based fluorescent probe that undergoes biothiol-promoted specific O–S cleavage and subsequent self-immolation through intramolecular 1,6-elimination. In addition, we investigated the cell viability of the system and successfully applied the probe to living cells, in vivo, and in various tissues.
Nickel foam was firstly used as a solid phase microextraction support to prepare temperature sensitive molecularly imprinted polymers using ofloxacin molecules as the template. The fluorescence intensity could be observed by the naked eye under ultraviolet light after ofloxacin adsorption onto the new materials, which was positively proportional to the adsorbance. After adsorption had occurred, the significantly different fluorescence intensities distinguished the molecularly imprinted polymers from the corresponding non-molecularly imprinted polymers. A detailed evaluation was made by different characterization methods and various adsorption experiments. Finally, the molecularly imprinted polymer on nickel foam was used as an adsorbent in solid phase microextraction, coupled with high performance liquid chromatography, to detect ofloxacin, norfloxacin and enrofloxacin in Yellow River water, obtaining recoveries of 93.2 to 108.3% and limits of quantification of 0.014 to 0.020 μg mL−1.
Journal of Materials Chemistry A 2014 vol. 2(Issue 22) pp:3433-3437
Publication Date(Web):28 Mar 2014
DOI:10.1039/C4TB00128A
We report here a novel doxorubicin (DOX) prodrug that reduces the proportion of inactive materials and minimizes drug leak. In aqueous solutions, the resulting DOX prodrug could spontaneously form stable micelles with diameters of ∼80 nm with a DOX loading content as high as ∼40 wt%. The subsequent cytotoxicity and cell internalization behavior indicated that the resulting prodrug could show a high in vitro anticancer efficacy. We believe that this strategy could be developed to design prodrugs of various anticancer drugs and thus offer new prodrugs for cancer therapy.
In the present study, a kind of single-hole glutathione (GSH)-responsive degradable hollow silica nanoparticles (G-DHSNs) was synthesized and used as carriers of doxorubicin (DOX) (DOX-G-DHSNs). The G-DHSNs were accurately designed and fabricated with a simple and convenient method, and without any extra pernicious component. The composition, morphology and properties of the G-DHSNs had been characterized by 1HNMR spectra, Fourier transform infrared spectrograph, thermo gravimetric analysis, transmission electron microscope, and scanning electron microscope. The degradation study of G-DHSNs showed that the G-DHSNs would be broken into pieces after interacting with GSH. Besides, the negligible hemolytic activity and low cytotoxicity of the G-DHSNs demonstrated its excellent biocompatibility. pH- and GSH-triggered release of DOX followed by the decomposition of G-DHSNs within TCA8113 cancer cells was further confirmed by flow cytometry and confocal laser scanning microscopy studies. All of these results indicated that G-DHSNs can be used as safe and promising drug nanocarriers.Keywords: cancer therapy; drug delivery; glutathione; hollow silica nanoparticles
ZnO quantum dots (QDs) with unique optical properties are potential useful tools for biological labeling and biosensing. With the increasing use of ZnO QDs, the toxicity evaluation of ZnO QDs is urgent. In this study, the hepatotoxicity including serum aminotransferases (ALT and AST), antioxidant enzymes (CAT, GSH-Px and SOD), lipid peroxidation and ultrastructure were evaluated after consecutive intravenous injection of ZnO QDs and ZnO QDs–PEG for 7 days in mice. Both ZnO QDs and ZnO QDs–PEG did not affect the coefficient of liver and the levels of serum aminotransferases. The antioxidant enzymes and lipid peroxidation had significant change after injecting 5 mg kg−1 ZnO QDs in 24 h, but all of these parameters returned to control levels in 28 days. ZnO QDs–PEG had a less harmful effect on antioxidant enzymes and malondialdehyde than ZnO QDs at the same dose. According to the results of hepatocyte ultrastructure, both ZnO QDs and ZnO QDs–PEG were located in the mitochondrion and induced nuclear malformation in 24 h. The ultrastructure of hepatocyte was as normal as of the control group in 28 days and ZnO QDs were mainly trapped in the mitochondrion while ZnO QDs–PEG mainly accumulated in the lysosomes. These findings would be helpful for wide use of quantum dots based bioimaging and biomedical applications in the future.
One molecule of zinc ion (Zn2+) could combine with two molecules of sulfadiazine (SDZ) to form a complex. Based on this concept, two experiments were performed to improve the preparation of sulfadiazine molecularly imprinted polymer materials (MIPs). One experiment used the complex of SDZ–Zn as template to replace SDZ in order to synthesize MIPs, which displayed higher selectivity and imprint factor. The second experiment used a methanol–acetic acid solution (9:1, v/v) containing 0.02 mol L−1 Zn2+ as the eluate to remove the template molecules from the synthesized MIPs, which could rapidly remove the template at 80 °C within two hours. Compared with the traditional Soxhlet extraction, the time was largely shortened.
A porous hollow molecular imprinting polymer (MIPs) with ofloxacin (OFL) as template and SiO2 nanoparticle (250 nm) as sacrifice core was synthesized. Dibutyl isophthalate was used as plasticizer to strengthen the polymer shell in MIP preparation firstly, which was necessary to avoid breaking the shell. Infrared spectra and transmission electron microscopy were used to verify the successful synthesis of the hollow MIPs. The adsorption behavior of MIPs was evaluated by adsorption capacity, imprint factor and adsorption model. The MIPs could obtain the adsorption capacity of 147 mg g−1 to OFL in theory and imprint factor of 2.6 when the initial OFL concentration was 900 μg mL−1. The MIPs could adsorb not only OFL but other fluoroquinolone antibiotics (FQs), which was useful to analyze FQs together. At the same time, it hardly adsorbed other compounds with dissimilar structure. The MIPs were used as adsorbent to enrich the FQs from milk and good selectivity and enrichment ratios were obtained. Coupling with high performance liquid chromatography, the FQs in milk were determined with no more than 30 ng mL−1 of the limit of quantitation.
In this paper, cystine- and cysteine-bonded stationary phases were synthesized and characterized by UV spectroscopy, Fourier transform infrared spectroscopy and elemental analysis which proved the successful immobilization of cystine and cysteine on the silica support. Both the new stationary phases displayed mixed-mode behavior, hydrophilic interaction chromatography (HILIC) mode and reversed-phase liquid chromatography (RPLC) mode. Retention behaviors of polar compounds on the two stationary phases were studied under different mobile phases by varying their water content, pH and ionic strength. The separation of sulfanilamide and substituted benzoic acid compounds was demonstrated on the new phases.
Chemistry – An Asian Journal 2014 Volume 9( Issue 1) pp:199-205
Publication Date(Web):
DOI:10.1002/asia.201301030
Abstract
We present here a novel camptothecin (CPT) prodrug based on polyethylene glycol monomethyl ether-block-poly(2-methacryl ester hydroxyethyl disulfide-graft-CPT) (MPEG-SS-PCPT). It formed biocompatible nanoparticles (NPs) with diameters of approximately 122 nm with a CPT loading content as high as approximately 25 wt % in aqueous solution. In in vitro release studies, these MPEG-SS-PCPT NPs could undergo triggered disassembly and much faster release of CPT under glutathione (GSH) stimulus than in the absence of GSH. The CPT prodrug had high antitumor activity, and another anticancer drug, doxorubicin hydrochloride (DOX⋅HCl), could also be introduced into the prodrug with a high loading amount. The DOX⋅HCl-loaded CPT prodrug could deliver two anticancer drugs at the same time to produce a collaborative cytotoxicity toward cancer cells, which suggested that this GSH-responsive NP system might become a promising carrier to improve drug-delivery efficacy.
•A series of novel polymers were prepared. Its synthesis was simple and cheap.•These polymers can interact with aflatoxins through non-covalent interactions.•The polymer I can be used as SPE sorbent to enrich the trace aflatoxins.A novel approach for assembling homogeneous hyperbranched polymers based on non-covalent interactions with aflatoxins was developed; the polymers were used to evaluate the extraction of aflatoxins B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2) in simulant solutions. The results showed that the extraction efficiencies of three kinds of synthesized polymers for the investigated analytes were not statistically different; as a consequence, one of the representative polymers (polymer I) was used as the solid-phase extraction (SPE) sorbent to evaluate the influences of various parameters, such as desorption conditions, pH, ionic strength, concentration of methanol in sample solutions, and the mass of the sorbent on the extraction efficiency. In addition, the extraction efficiencies for these aflatoxins were compared between the investigated polymer and the traditional sorbent C18. The results showed that the investigated polymer had superior extraction efficiencies. Subsequently, the proposed polymer for the SPE packing material was employed to enrich and analyze four aflatoxins in the cereal powder samples. The limits of detection (LODs) at a signal-to-noise (S/N) ratio of 3 were in the range of 0.012–0.120 ng g−1 for four aflatoxins, and the limits of quantification (LOQs) calculated at S/N = 10 were from 0.04 to 0.40 ng g−1 for four aflatoxins. The recoveries of four aflatoxins from cereal powder samples were in the range of 82.7–103% with relative standard deviations (RSDs) lower than 10%. The results demonstrate the suitability of the SPE approach for the analysis of trace aflatoxins in cereal powder samples.
Journal of Chromatography A 2013 Volume 1302() pp:28-33
Publication Date(Web):9 August 2013
DOI:10.1016/j.chroma.2013.06.033
•We used click reaction to prepare a new type of polymer as the monolith column.•The polymer was porous and could enrich PAHs well up to 100 to more than 1000 times.•The π–π stacking interaction and the effect of small size played dominant roles to the strong adsorption affinity of the polymer monolith.•A sensitive on-line SPME–HPLC method was set up for determination of PAHs.A polymer monolith column was prepared using click chemistry for on-line solid phase microextraction of polycyclic aromatic hydrocarbons (PAHs), using 2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene(TES) and 1,4-bis(6-azidoalkoxy)benzene (BAB) as monomers, and Cu(PPh3)3Br as the catalyst. The polymer with spirocyclic cross-links was porous and presented an appropriate interspace of PAHs. Enrichment of PAHs, in the range of 100 to more than 1000 times, was due to the π–π stacking interaction and the effect of small size. The factors affecting the on-line microextraction efficiency were optimized, and the analytical conditions were evaluated to ensure reliability.
Core–shell structured multifunctional nanocarriers (NCs) of ZnO quantum dots-conjugated gold nanoparticles (Au NPs) as core and amphiphilic hyperbranched block copolymer as shell were synthesized for targeted anticancer drug delivery. The amphiphilic hyperbranched block copolymer contained poly(l-lactide) (PLA) inner arm and folate (FA)-conjugated a sulfated polysaccharide from Gynostemma pentaphyllum Makino (GPPS-FA) outer arm. The structure and properties of core–shell structured multifunctional nanocarriers were characterized and determined by UV–visible spectra, FT-IR spectra, X-ray diffraction (XRD), fluorescence spectroscopy and TEM analyses. The release results indicated that camptothecin (CPT) release from NCs at pH 7.4 was much greater than that at pH 5.3. The cytotoxicity studies showed that both the blank NCs and the CPT-loaded NCs provided high anticancer activity against Hela cells. Furthermore, nanocarriers gained specificity to target model cancer cells in this study due to the enhanced cell uptake mediated by FA moiety. The results indicated that the NCs not only had great potential as tumor-targeted drug delivery nanocarrier, but also had an assistant role in the treatment of cancer.Highlights► We synthesized core–shell structured multifunctional nanocarriers. ► Nanocarriers had great potential as tumor-targeted drug delivery nanocarrier. ► Nanocarriers had certain antitumor activities. ► Tumor cells could be killed by the cooperation of nanocarriers and drugs.
Arthus reaction (AR), a type of unconventional immune complex-mediated inflammation, is likely accompanied by alterations in circulating metabolites. Here, a proton nuclear magnetic resonance (1H NMR) spectroscopy method coupled with a rapid resolution liquid chromatography (RRLC) method was developed to evaluate the systemic metabolic consequences of AR and characterize metabolic aberrations. Serum and urine samples from AR rats and normal controls were compared to determine whether there were significant alterations associated with AR. The partial least squares discriminant analysis (PLS-DA) models of metabolomic results demonstrated good intergroup separations between AR rats and normal controls. Multivariate statistical analysis revealed significant alterations in the levels of 34 metabolites, which were termed as the disease-associated biomarkers. Differential metabolites identified from the metabolomic analysis suggested that AR caused dysfunctions of kidney and liver accompanied with changes in widespread metabolic pathways including the tricarboxylic acid (TCA) cycle, gut microbiota metabolism, lipids and cell membranes metabolism, glucose metabolism, fatty acid β-oxidation, amino acids metabolism and ketogenesis. This study assessed and provided important metabolomic variations in serum and urine associated with AR and, therefore, demonstrated metabolomics as a powerful approach for the complete elucidation of the underlying pathophysiologic mechanisms of AR.
Co-reporter:Zhigang Xu, Kelin Zhang, Xiaoyan Liu and Haixia Zhang
RSC Advances 2013 vol. 3(Issue 39) pp:17700-17702
Publication Date(Web):07 Aug 2013
DOI:10.1039/C3RA43098G
We have synthesized novel glutathione (GSH) responsive silica nanoparticles by introducing disulfide bonds into silica nanoparticles, which are highly uniform in size and show excellent blood compatibility. The subsequent degradation process under physiological conditions shows their promising potential for medical treatment and diagnosis.
In this paper, linear and cyclic tetrapeptide bonded stationary phases, were synthesized by the solid-phase synthesis method. Each amino acid coupling step was monitored by the ninhydrin test using UV/visible spectrophotometry. The proposed materials were characterized by UV spectroscopy, Fourier transform infrared spectroscopy, elemental analysis and thermogravimetric analysis, which proved the successful immobilization of tetrapeptide on the silica support. The cyclopeptide stationary phase displayed mixed-mode behavior and had the size selectivity for polycyclic aromatic hydrocarbon such as anthracene, while the linear peptide stationary phase only exhibited typical hydrophilic interaction chromatography (HILIC) characteristics and was more hydrophilic under the same mobile phase condition. Retention behaviors of polar compounds on the two stationary phases were studied through varying column temperature, the water content, pH and ionic strength in mobile phase. Applications in the separation of the mixture of nucleosides, sulfa compounds, organic acids and isomers of substituted benzoic acid compounds were demonstrated.Highlights► Novel linear and cyclic tetrapeptide bonded stationary phases were synthesized. ► The cyclopeptide phase displayed mixed-mode behavior and size selectivity. ► The linear peptide stationary phase only exhibited typical HILIC characteristics. ► Some kinds of polar compounds were separated on the two stationary phases.
Co-reporter:Min Guan ; Wendong Wang ; Eric J. Henderson ; Ömer Dag ; Christian Kübel ; Venkata Sai Kiran Chakravadhanula ; Julia Rinck ; Igor L. Moudrakovski ; Jordan Thomson ; Jeffrey McDowell ; Annie K. Powell ; Haixia Zhang ;Geoffrey A. Ozin
Journal of the American Chemical Society 2012 Volume 134(Issue 20) pp:8439-8446
Publication Date(Web):April 18, 2012
DOI:10.1021/ja209532e
A contemporary question in the intensely active field of periodic mesoporous organosilica (PMO) materials is how large a silsesquioxane precursor can be self-assembled under template direction into the pore walls of an ordered mesostructure. An answer to this question is beginning to emerge with the ability to synthesize dendrimer, buckyball, and polyhedral oligomeric silsesquioxane PMOs. In this paper, we further expand the library of large-scale silsesquioxane precursors by demonstrating that photoluminescent nanocrystalline silicon that has been surface-capped with oligo(triethoxysilylethylene), denoted as ncSi:(CH2CH2Si(OEt)3)nH, can be self-assembled into a photoluminescent nanocrystalline silicon periodic mesoporous organosilica (ncSi-PMO). A comprehensive multianalytical characterization of the structural and optical properties of ncSi-PMO demonstrates that the material gainfully combines the photoluminescent properties of nanocrystalline silicon with the porous structure of the PMO. This integration of two functional components makes ncSi-PMO a promising multifunctional material for optoelectronic and biomedical applications.
Two kinds of core–shell structured multifunctional nanocarriers of gold nanoclusters (Au NCs) as core and folate (FA)-conjugated amphiphilic hyperbranched block copolymer as shell based on poly(l-lactide) (PLA) inner arm and FA-conjugated sulfated polysaccharide (GPPS–FA) outer arm (Au NCs-PLA-GPPS-FA) were synthesized for targeted anticancer drug delivery. The structure and properties of Au NCs-PLA-GPPS-FA copolymers were characterized and determined by 1H NMR spectrum, FT-IR spectra, dynamic light scattering (DLS), fluorescence spectroscopy, and transmission electron microscopic (TEM) analyses. The anticancer drug, camptothecin (CPT) was used as a hydrophobic model anticancer drug. In vitro, two kinds of the nanocarriers presented a relatively rapid release in the first stage (up to 1 h) followed by a sustained release period (up to 15 h), and then reached a plateau at pH 5.3, 7.4, and 9.6. The release results indicated that CPT release from two kinds of the nanocarriers at pH 9.6 was much greater than that at both pH 5.3 and 7.4. The cytotoxicity studies showed that the CPT-loaded nanocarriers provided high anticancer activity against Hela cells. Furthermore, nanocarriers gained specificity to target some cancer cells because of the enhanced cell uptake mediated by FA moiety. The fluorescent images studies showed that the nanocarriers could track at the cellular level for advance therapy. The results indicated that the Au NCs-PLA-GPPS-FA copolymers not only had great potential as tumor-targeted drug delivery carrier, but also had an assistant role in the treatment of cancer.Keywords: Au NCs; cytotoxicity; drug delivery; nanocarriers;
A core–shell structured multifunctional carrier with nanocrystalline silicon (ncSi) as the core and a water-soluble block copolymer as the shell based on a poly(methacrylic acid) (PMAA) inner shell and polyethylene glycol (MPEG) outer shell (ncSi-MPM) was synthesized for drug delivery. The morphology, composition, and properties of the resulting ncSi-MPM were determined by comprehensive multianalytical characterization, including 1H NMR spectroscopy, FTIR spectroscopy, XPS spectroscopy, TEM, DLS, and fluorescence spectroscopy analyses. The size of the resulting ncSi-MPM nanocarriers ranged from 40 to 110 nm under a simulated physiological environment. The loading efficiency of model drug doxorubicin (DOX) was approximately 6.1–7.4 wt % for ncSi-MPM and the drug release was pH controlled. Cytotoxicity studies demonstrated that DOX-loaded ncSi-MPM showed high anticancer activity against Hela cells. Hemolysis percentages (<2%) of ncSi-MPM were within the scope of safe values. Fluorescent imaging studies showed that the nanocarriers could be used as a tracker at the cellular level. Integration of the above functional components may result in ncSi-MPM becoming a promising multifunctional carrier for drug delivery and biomedical applications.Keywords: controlled release; cytotoxicity; drug delivery; nanocrystalline silicon;
We developed a novel chitosan-based luminescent/magnetic hybrid nanoparticles with folate-conjugated tetrapeptide composites (CLMNPs-tetrapeptide-FA) by conjugation in situ. First, chitosan, CdTe quantum dots (QDs), and superparamagnetic iron oxide were directly gelled into ternary hybrid nanogels. Subsequently, tetrapeptides (GFFG and LGPV) and folate were conjugated orderly into the hybrid nanoparticles. The morphology, composition, and properties of the as-prepared copolymers have also been characterized and determined using TEM, EDX, XRD, FTIR spectra, DLS, fluorescence spectroscopy, VSM, and fluorescence microscopy imaging studies. The size range of the end product CLMNPs-tetrapeptide-FA copolymers was from 150 to 190 nm under simulated physiological environment. In vivo, the experimental results of magnetic accumulation showed that the copolymers could be trapped in the tumor tissue under magnetic guidance. Under the present experimental conditions, the loading efficiencies of CPT were approximately 8.6 wt % for CLMNPs-GFFG-FA and 1.1 wt % for CLMNPs-LGPV-FA, respectively. The CPT cumulative release under dialysis condition mainly occurred for the first 28 h, and could reach 55% at pH 5.3 and 46% at pH 7.4 from CPT-loaded CLMNPs-GFFG-FA, and 69% at pH 5.3 and 57% at pH 7.4 from CPT-loaded CLMNPs-LGPV-FA within 28 h, respectively. The hemolysis percentages (<2%) and coagulation properties of blank and CPT-loaded copolymers were within the scope of safe values. Compared to free CPT, the CPT-loaded CLMNPs-tetrapeptide-FA copolymers showed specific targeting to A549 cells in vitro. More than 75% viability in L02 cells were seen in CLMNPs-GFFG-FA and CLMNPs-LGPV-FA copolymer concentration of 500 μg/mL, respectively. It was found that the two kinds of copolymers were transported into the A549 cells by a folate-receptor-mediated endocytosis mechanism. These results indicate that the multifunctional CLMNPs-tetrapeptide-FA copolymers possess a moderate CPT loading efficiency, low cytotoxicity, and favorable biocompatibility, and are promising candidates for tumor-targeted drug delivery.
Carbon nanoparticles (CNPs) (6–18 nm in size) were prepared by refluxing corn stalk soot in nitric acid. The obtained acid-oxidized CNPs are soluble in water due to the existence of carboxylic and hydroxyl groups. 13C NMR measurement shows the CNPs are mainly of sp2 and sp3 carbon structure different from CNPs obtained from candle soot and natural gas soot. Furthermore, these CNPs exhibit unique photoluminescence properties. Interestingly, the CNPs might be exploited to immobilize on the surface of porous silica particles as chromatographic stationary phase. The resultant packing material was evaluated by high-performance liquid chromatography, indicating that the new stationary phase could be used in hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes. The separation of five nucleosides, four sulfa compounds and safflower injection was achieved by using the new column in the HILIC and PALC modes, respectively.Graphical abstractHighlights► Carbon nanoparticles (6–18 nm in size) were prepared from corn stalk soot. ► CNPs-based silica were used as novel chromatography stationary phase. ► The new phase shows good separation selectivity for polar compounds. ► The new phase had the similar retention for polar probes in HILIC and PALC modes. ► In contrast to PALC, under HILIC conditions high efficiencies were achieved.
Journal of Chromatography A 2012 Volume 1229() pp:72-78
Publication Date(Web):16 March 2012
DOI:10.1016/j.chroma.2012.01.042
A molecularly imprinted polymer was synthesized by ultrasonic irradiation, with attapulgite as matrix using β-naphthol as the template molecule, acryloyl-β-cyclodextrin as the functional monomer, and N,N-methylenebiacrylamide as the cross-linking agent, respectively. The imprinted polymer was characterized by infrared spectroscopy and transmission electron microscopy. Compared to polymers prepared by traditional heat sources, the molecularly imprinted polymer synthesized by ultrasonic irradiation had better selectivity and faster adsorption kinetics to estriol, estradiol, estrone and diethylstilbestrol. Using the imprinted polymer as the packing material for on-line solid-phase extraction, the above four estrogens in milk samples were concentrated and analyzed. The limits of detection for these estrogens were in the range of 1–8 ng g−1 and reproducibility were less than 5.1% as RSDs (n = 6) with milk samples spiked at 100 and 1000 ng g−1 of each analyte.Highlights► Molecularly imprinted polymer was synthesized by ultrasonic irradiation. ► Ultrasonic irradiation provides short duration of high temperatures and pressures. ► It has better selectivity and faster adsorption kinetics to estrogens. ► A sensitive on-line SPE–HPLC method was set up for determination of estrogens.
We developed a novel folate conjugated carboxymethyl chitosan-ferroferric oxide doped cadmium telluride quantum dot nanoparticles (abbreviate: CFLMNPs). Processing parameters affected the end product properties were optimized systematically. The morphology, composition, and properties of the as-prepared CFLMNPs have also been characterized and determined using TEM, SEM, DLS, FT-IR spectra, EDX, fluorescence spectroscopy, VSM, XRD and LSCM studies. The resulting CFLMNPs possessed intense superparamagnetic effect and photoluminescence (PL) property at room temperature. The size range of CFLMNPs was from 170 to 190 nm under simulate physiological environment. The anticancer drug selected in this study was adriamycin which can be used for the human liver cancer treatment. Under present experiment condition, the loading efficiency of ADM was approximately 36.6 wt% for CFLMNPs. The cumulative release under sink condition mainly occurred for the first 24 h, and could reach 36% at pH 5.3 and 15% at pH 7.4 within 24 h. 85% and 70% of viability of L02 and HepG2 cells were watched at a blank CFLMNPs concentration of 1 mg/mL, respectively. It is found that the CFLMNPs were transported into the HepG2 cells by an folate-receptor-mediated endocytosis mechanism. These results indicate that the multifunctional CFLMNPs possess a high drug loading efficiency, low cytotoxicity and favorable cell compatibility, and are promising candidates for carboxymethyl chitosan-based targeted drug delivery and cellular imaging.Highlights► Magnetic, luminescent and specific multifunctional nanoparticles are obtained. ► Processing parameters strongly affect the resulting end product properties. ► The drug carrier are stable under simulate physiological environment. ► Biocompatible drug carrier displays pH-regulated release profile in vitro. ► Nanoparticles designed can be applied in drug delivery and cell imaging.
The periodic mesoporous organosilicas (PMO) with an organobridged (CH2) was synthesized and functionalized with amino or carboxylic groups by post-synthesis methods. The functionalized PMO by changing the hydrophilic/hydrophobic property and the net charge could be used to selectively adsorb and purify proteins with different shapes and different isoelectric points (pI). The experimental result showed that Bovine serum albumin (BSA) was adsorbed quicker than hemoglobin (Hb) on the materials, and lysozyme (Lys) could not be adsorbed on these PMO materials at all. The adsorption capacity of amino groups modified PMO (PMO-(NH2)2) for BSA was 44.67 mg/g and 300.0 mg/gfor Hb on carboxylic groups modified PMO (PMO-(COOH)2). The adsorption behavior of proteins was affected strongly by the interaction among different constituents in the mixture of proteins. In addition, it is found that the adsorption rate of (PMO-(NH2)2 for adsorption of proteins was much slower than PMO-(COOH)2.
Journal of Chromatography B 2012 Volume 906() pp:91-95
Publication Date(Web):1 October 2012
DOI:10.1016/j.jchromb.2012.08.030
A rapid resolution liquid chromatography (RRLC) method was developed for the simultaneous determination of 23 amino acids in rat serum after pre-column derivatization with 2,4-dinitrofluorobenzene (DNFB). The amino acid derivatives were separated on an Agilent Zorbax Eclipse Plus C18 (4.6 mm × 50 mm, 1.8 μm) column at 45 °C. Ultraviolet (UV) detection was set at 360 nm. Good separation of 23 amino acids was achieved within 10 min with a ternary gradient elution of mobile phase at a flow rate of 1.5 mL min−1. Calibration curves were linear over the range from 1 to 500 μmol L−1 with coefficients 0.9962 or better for each amino acid. The lower limits of quantification (LLOQ) of all 23 amino acids were 1 μmol L−1 with signal-to-noise (S/N) ratio ≥4. Intra- and Inter-day precisions, expressed as relative standard deviation (RSD) percentages, were ranged from 0.32% to 3.09% and 0.67% to 5.82%, respectively. Finally, it was successfully applied to the determination of amino acids in rat serum with recoveries ranged from 90.8% to 106.0% and RSD percentages ranged from 1.78% to 4.68%, respectively. The results showed that the proposed method provided a shorter elution time, better resolution and sharper peak shapes for all amino acids. Compared with the conventional high performance liquid chromatography (HPLC) methods, even some ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS), the established RRLC method was superior performance.Highlights► The RRLC method was the first time used for amino acids detection. ► Compared with common HPLC and some UPLC, the RRLC was superior performance. ► The reduced solvent consumption was friendly to environment protection. ► The RRLC based on UV detection was economic and available in common laboratories.
A native polysaccharides (GPP2) was isolated from Gynostemma pentaphyllum Makino. Four sulfated derivatives of GPP2 (GPP2-s1 to s4) were prepared by chlorosulfonic acid method with ionic liquids (ILs) as solvent and 4-dimethylaminopyridine (DMAP) as catalyst. The structures of the sulfated derivatives were analyzed by FT-IR spectra and 13C NMR spectra, which indicated that the sulfated groups were introduced mainly at the C-6 position as well as at the C-2 position. The products showed different degree of substitution (DS) ranging from 0.79 to 1.34, and different weight-average molecular mass (Mw) ranging from 8.64 to 11.2 Da. The sulfated derivatives inhibited the growth of HepG2 cells and Hela cells in vitro significantly. Furthermore, they had no obvious influence on 293 cells, which indicated that they had low toxicity. Flow cytometric studies revealed that treatment of the sulfated derivatives with Hela cells could mediate the cell-cycle arrest in the S phase.
Journal of Chromatography A 2011 Volume 1218(Issue 35) pp:5987-5994
Publication Date(Web):2 September 2011
DOI:10.1016/j.chroma.2011.04.023
An imidazoline was prepared by solvent-free microwave-assisted organic synthesis and immobilized on porous silica particles by polymerization. The resulting material was composed of both hydrophobic alkyl ester chains and hydrophilic imidazoline rings, which gave it both hydrophilic interaction and reversed-phase characteristics. The titration curve suggests that the new material has buffering capacity and acquires increasing positive charge over the pH range 9–4, and is “zwitterionic” in the upper part of this pH range. Through investigating the effect of column temperature, the water content, pH and ion strength of mobile phase on the retention time of polar compounds in highly organic eluents, it was found that the new material could be used as a hydrophilic interaction liquid chromatography (HILIC) stationary phase which involved a complex retention process consisting of partitioning, surface adsorption and electrostatic interactions. In addition, the retention behavior of aromatic compounds in different mobile phase conditions was also studied, which showed the new material mainly exhibited a partitioning mechanism in the reversed-phase liquid chromatography (RPLC) mode. The separation of six water-soluble vitamins and five aromatic compounds were achieved by using the new material in the HILIC and RPLC modes, respectively.
Journal of Chromatography A 2011 Volume 1218(Issue 11) pp:1503-1508
Publication Date(Web):18 March 2011
DOI:10.1016/j.chroma.2011.01.044
The mixed sulfated/methacryloyl polysaccharide derivative was prepared and successfully immobilized onto the surface of porous silica particles by polymerization. Polysaccharide derivative was calculated as 10.33% in the stationary phase prepared. The new stationary phase (PMSP) showed both hydrophilic interaction (HILIC) and per aqueous liquid chromatography (PALC) characteristics. The effects of column temperature, the water content, pH and ion strength of mobile phase on the retention time of test compounds in highly aqueous eluents were investigated to evaluate the PALC features of PMSP. The column efficiency is about 31,000 plates/m for benzoic acid in water/ACN (97/3, v/v) mobile phase at a flow rate of 1.0 mL/min. Compared with C18 column, the PMSP had shorter retention time for weak polar and non-polar compounds, but also showed stronger retention for strong polar compounds. It indicated that PALC was a suitable mode of chromatography as replacement of HILIC and complementarity of reversed-phase liquid chromatography (RPLC).
Co-reporter:Xiaoyan Liu, Ting Zhao, Jingfeng Lan, Ling Zhu, Wenfu Yan and Haixia Zhang
Analyst 2011 vol. 136(Issue 22) pp:4710-4717
Publication Date(Web):03 Oct 2011
DOI:10.1039/C1AN15556C
Selective enrichment or removal of specific proteins prior to analysis can minimize nonspecific interferences as well as information loss, which has been an important issue in current proteomics fields. In this work, two kinds of mesoporous silica SBA-15 (mean pore diameter of 5 nm and 7 nm), bifunctionalized with quaternary ammonium and C18 groupsvia silylanization reaction, was used to investigate the adsorption behavior for different proteins (bovine serum albumin (BSA), ovalbumin (OVA), hemoglobin (Hb), lysozyme (Lys) and cytochrome c (cyt c)). As possessing anion exchange (quaternary ammonium) groups, the bifunctionalized SBA-15 showed selective adsorption of the negative charged proteins, BSA and OVA. Based on these properties, sequential fractionation based on different SBA-15 materials as micropipette tip sorbents was developed for sample preparation prior to protein analysis. As expected, after the sequential treatment of the sample, the detection signal of the high abundant BSA was significantly decreased and that of the low abundant cyt c was obviously enlarged, which solved the problem that low abundant protein was suppressed by adjacent high abundant protein. The sample preparation technique significantly improved protein identification and this sequential fractionation approach could be potentially applied to extend information on the protein identification for biological samples with a wide dynamic range.
Microporous and Mesoporous Materials 2011 Volume 142(2–3) pp:614-620
Publication Date(Web):July 2011
DOI:10.1016/j.micromeso.2011.01.008
Sulfonic acid-functionalized SBA-15 mesoporous molecular sieve (SBA-15-SO3H and SBA-15-po-SO3H) were synthesized by two post-synthesis methods. The functionalized SBA-15 materials were characterized and used to investigate the adsorption behavior for proteins (bovine serum albumin and cytochrome c) and polypeptides (insulin and glucagon) in the static and dynamic processes. The adsorption conditions: including adsorption time, pH and ionic strength of sample solution were investigated in the static adsorption mode. Under optimal conditions, SBA-15-SO3H and SBA-15-po-SO3H had a maximum capacity for insulin of 430 and 451 mg/g and for glucagon of 1303 and 1094 mg/g, respectively. In addition, the two functionalized SBA-15 mesoporous materials showed selectively adsorption of proteins in the dynamic adsorption mode. Compared with SBA-15, the surface modification of SBA-15 was responsible for the selective adsorption of proteins and high adsorption capacity for some biomolecules. It indicated that the two functionalized materials could be used as adsorbents to immobilize or separate biomolecules.Graphical abstractResearch highlights► Two strong cation-exchange SO3H modified SBA-15 materials were synthesized. ► Two modified SBA-15 could selectively adsorb proteins in the dynamic mode. ► Two modified SBA-15 had large loading capacity for polypeptides in the static mode.
Journal of Molecular Catalysis A: Chemical 2011 Volumes 342–343() pp:74-82
Publication Date(Web):1 June 2011
DOI:10.1016/j.molcata.2011.04.014
Esterification of polysaccharide had been carried out by catalysis using a series of catalysts, which were synthesized by H3PW12O40 (HPW) immobilized on chloromethylated polystyrene bead (PSC) and named as PS-EDA-HPW, PS-DETA-HPW, PS-TETA-HPW and PS-(AST-HPW)n according to different linker in the reaction system. The catalysts were characterized by FTIR spectroscopy, nitrogen adsorption, X-ray diffraction and inductively coupled plasma atomic emission spectrophotometer. PS-(AST-HPW)n showed the highest efficacy on esterification of polysaccharide. Four phosphorylated derivatives (POP1-p) of a native polysaccharide (POP1) from Portulaca oleracea L. with different degree of substitution (DSp) were obtained using PS-(AST-HPW)n as the catalyst. Chemical equilibrium was established as quickly as 10 h with the content of P more than 5%. Compared with native POP1, POP1-p exhibited superior antioxidant activities in vitro, which indicated that phosphorylated modification could enhance antioxidant activities of POP1. It was obvious that the DSp had a significant effect on the antioxidant activity.Graphical abstractCatalysts were synthesized for polysaccharide esterification by H3PW12O40 (HPW) immobilized on chloromethylated polystyrene bead (PSC), and were characterized by FTIR spectroscopy, nitrogen adsorption, X-ray diffraction and inductively coupled plasma atomic emission spectrophotometer.Highlights► Esterification of biomacromolecules was carried out by solid catalysis. ► Antioxidant activities of polysaccharide were increased by molecular modification. ► Catalysis was synthesized by H3PW12O40 immobilized on polystyrene bead.
A porous polysulfone microcapsule containing organic modified montmorillonite and magnetic nanoparticles (OMMT-Fe3O4@PSF) has been successfully prepared by a phase-inversion method and evaluated as a magnetic solid-phase extraction (MSPE) sorbent for clean-up and enrichment of 4-chlorophenol (4-CP) and 2-chlorophenol (2-CP) in aqueous samples. Compared with a microcapsule containing the conventional extraction sorbent C18 (C18-Fe3O4@PSF), OMMT-Fe3O4@PSF had much lower cost, a faster adsorption rate, and superior uptake amounts for the investigated analytes. The proposed microcapsule has been developed for the extraction of 4-CP and 2-CP from environmental water samples and their analysis by high-performance liquid chromatography with UV detection (HPLC-UV). Various parameters, such as pH, extraction time, the mass of sorbent, and the desorption conditions, have been evaluated and the calibration curves of the chlorophenols were linear (R2 ≥ 0.9985) in the range from 1.01 to 104.5 ng mL−1. The limits of detection at a signal-to-noise (S/N) ratio of 3 were 0.22 and 0.17 ng mL−1 and the limits of quantification calculated at S/N = 10 were 1.52 and 1.07 ng mL−1 for 2-CP and 4-CP, respectively. The recoveries of 2-CP and 4-CP from natural water and the treated wastewater samples were in the range of 84.4–115% with relative standard deviations (RSDs) lower than 7.0%. The results have demonstrated the suitability of the MSPE approach for the analysis of trace chlorophenols in aqueous samples.
Co-reporter:Zhigang Xu, Bo Li, Wanjin Tang, Tong Chen, Haixia Zhang, Qin Wang
Colloids and Surfaces B: Biointerfaces 2011 Volume 88(Issue 1) pp:51-57
Publication Date(Web):1 November 2011
DOI:10.1016/j.colsurfb.2011.05.055
In this work, glycopolypeptide nanoparticles (GPNPs) composed of Mn doped ZnS quantum dots (QDs) as core and glycopolypeptides as shell were synthesized through the surface initiated polymerization of N-carboxyanhydrides and surface condensation polymerization with carboxymethyldextran on amine-functionalized QDs. The loading and release behavior of ibuprofen on the GPNPs were investigated. The GPNPs exhibited not only high loading but also controlled release behavior. The cytotoxicity of the GPNPs was evaluated by incubating with HEK293T cell lines and they were shown to be of low cytotoxicity. They appear to be a very promising candidate for targeted drug delivery.Graphical abstractHighlights• Multifunctional core–shell structured glycopolypeptide nanoparticles were fabricated by NCA chemistry. • Glycopolypeptides shell was dextran-poly(l-alanine) and could offer rich –OH and –NH2 for combining drug by multi-bond effect. • Glycopolypeptide nanoparticles are a low-cytotoxic material.
In this work, a poly-l-lysine-grafted stationary phase was synthesized by polymerization of N-carboxyanhydride of l-lysine initiated by 3-aminopropylated silica. The resulting material was characterized by FT-IR spectra, elemental analysis and thermogravimetric analysis, which clearly indicated that the new phase had been prepared successfully. The retention of polar solutes depending on acetonitrile content in mobile phase exhibited “U-shaped” curves, which was an indication of hydrophilic interaction liquid chromatography (HILIC)/reversed-phase liquid chromatography (RPLC) mixed-mode retention behavior. The retention mechanisms in HILIC and RPLC modes also were investigated. Phenol compounds, aniline compounds and hydrophilic compounds were separated in RPLC or HILIC mode on the new stationary phase, respectively. This result shows that the new phase could be used for both RPLC and HILIC applications, providing greater flexibility for real sample analysis.
Journal of Chromatography A 2010 Volume 1217(Issue 45) pp:6995-7002
Publication Date(Web):5 November 2010
DOI:10.1016/j.chroma.2010.09.005
A novel molecularly imprinted polymer was synthesized with attapulgite employed as matrix, which is simple and time-saving. In this method, sudan I was chosen as template molecule, 2-vinylpyridine as functional monomer and ethylene glycol dimethacrylate as cross-linking agent, respectively. The imprinted polymer was characterized by the infrared spectroscopy and transmission electron microscopy. Then the selectivity experiments were performed on sudan dyes and the recognition coefficients for sudan I, sudan II, sudan III and sudan IV were 2.9, 1.9, 1.9 and 2.3, respectively. As the packing material of solid-phase extraction, the imprinted polymer has been applied to on-line concentration of the four sudan dyes in samples from Yellow River water, tomato sauce and sausage. The corresponding analytical methods to determine these sudan dyes have been developed. The limits of detection for these sudan dyes were in the range of 0.01–0.05 ng mL−1 for Yellow River water, 1.0–3.0 ng g−1 for tomato sauce and 0.8–3.0 ng g−1 for sausage.
In this study, an amphiphilic bifunctional mesoporous SBA-15 material (AMPBIF-SBA-15) was synthesized through post-synthesis method as a drug carrier. Ribavirin was selected as the model drug and whose release from both unmodified and functionalized SBA-15 was evaluated in four media solutions with different pH or ionic strength. The release process indicated that AMPBIF-SBA-15 was a pH-sensitive drug carrier, which showed a phased low-release effect to ribavirin in the simulated body fluid (PBS, pH 7.4) solution. The materials were further characterized by Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption–desorption measurements and elemental analysis. This study provided a novel drug carrier for ribavirin to improve curative effect of ribavirin.
Colloids and Surfaces B: Biointerfaces 2010 Volume 81(Issue 2) pp:503-507
Publication Date(Web):1 December 2010
DOI:10.1016/j.colsurfb.2010.07.048
A novel Fe3O4@SiO2@poly-l-alanine peptide brush–magnetic microsphere (PBMMs) was synthesized from amine-functionalized Fe3O4 through the surface-initiated polymerization of N-carboxyanhydrides. Two materials with different peptide lengths were obtained from different amounts of N-carboxyanhydrides. These materials were characterized by Fourier transform infrared, transmission electron microscopy, large-angle powder X-ray diffraction, vibrating sample magnetometer and elemental analysis. Furthermore, the loading and release behavior of ibuprofen and the enrichment of bovine serum albumin on the two materials were investigated and it was shown that the PBMMs have a maximum uptake amount of ibuprofen of 40.3 mg g−1, and an enrichment of bovine serum albumin of 20.9 mg g−1. These materials are promising candidates for targeted drug delivery and protein enrichment.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2010 Volume 75(Issue 5) pp:1584-1591
Publication Date(Web):May 2010
DOI:10.1016/j.saa.2010.02.023
The binding of mangiferin to insulin and glucagon was investigated in the presence and absence of another Peptide by optical spectroscopy. Fluorescence titration experiments revealed that mangiferin quenched the intrinsic fluorescence of insulin and glucagon by static quenching. The ratios of binding constants of glucagon-mangiferin to insulin-mangiferin at different temperatures were calculated in “pure” and ternary system, respectively. The results indicated that the Peptides were competitive with each other to act on mangiferin. Values of the thermodynamic parameters and the experiments of pH effect proved that the key interacting forces between mangiferin and the Peptides were hydrophobic interaction. In addition, UV–vis absorption, synchronous fluorescence and Fourier transform infrared measurements showed that the conformation of insulin and glucagon were changed after adding mangiferin.
A water-soluble polysaccharide (POP1) was isolated from Portulaca oleracea L. Four sulfated derivatives of POP1 (POP1-s1, POP1-s2, POP1-s3 and POP1-s4) were prepared by chlorosulfonic acid method with N,N-Dicyclohexylcarbodiimide (DCC) as a dehydration-condensation agent. FT-IR spectra and 13C NMR spectra indicated the sulfated groups had been introduced at the C-6 and C-2 positions of POP1. Sulfated derivatives had different degree of substitution (DS) ranging from 1.01 to 1.81, and different weight-average molecular mass (Mw) ranging from 41.4 to 48.5 KDa. Sulfated derivatives except POP1-s5 inhibited the growth of HepG2 cells and Hela cells in vitro significantly, which indicated that sulfated modification could enhance cytotoxicity of POP1 on tumor cells. Flow cytometric studies revealed that sulfated derivatives could mediate the cell-cycle arrest of Hela cells in the S phase.
Co-reporter:Chuande Zhao, Yongsheng Ji, Yongliang Shao, Xiaoman Jiang, Haixia Zhang
Journal of Chromatography A 2009 Volume 1216(Issue 44) pp:7546-7552
Publication Date(Web):30 October 2009
DOI:10.1016/j.chroma.2009.06.011
Using nanoattapulgite as matrix, both diethylstilbestrol surface molecularly imprinted polymer and non-imprinted polymer were synthesized in this work. Compared with each other, the diethylstilbestrol surface molecularly imprinted polymer is superior to non-imprinted polymer in adsorption capacity, selectivity and mass transfer property. The maximum static adsorption capacities of diethylstilbestrol surface molecularly imprinted polymer, non-imprinted polymer and nanoattapulgite for diethylstilbestrol was 105.14, 78.54 and 28.50 mg g−1, respectively. As the packing material of solid-phase extraction, the diethylstilbestrol surface molecularly imprinted polymer has been applied to concentrating diethylstilbestrol in pond water and fish samples. A corresponding analytical method to determine diethylstilbestrol has been developed. The limit of detection for diethylstilbestrol in pond water sample and fish samples were 3 μg L−1 and 15 μg kg−1.
Microporous and Mesoporous Materials 2009 Volume 123(1–3) pp:193-201
Publication Date(Web):1 July 2009
DOI:10.1016/j.micromeso.2009.04.001
Mesoporous SBA-15 molecular sieves, with large surface area and homogeneous pore diameters, are commonly used as catalysts and adsorbents. In this work, SBA-15 was functionalized with 3-(methacryloyloxy)propyltrimethoxysilane (MPTMS) and then polymerized sol–gel onto the channel walls. The new materials were characterized by solid-state NMR, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and elemental analysis. The adsorption properties of SBA-15, MPTMS modified SBA-15 and polymerized sol–gel SBA-15 to Rhodamine B (RB) were studied comparably. The modified SBA-15 materials have effective adsorption characters to RB. These results demonstrate that these new materials have potential applications in the treatment of RB pollution from environment.
Co-reporter:Yongsheng Ji;Xiaoyan Liu;Min Guan;Chue Zhao;Huayu Huang;Haixia Zhang;Chunming Wang
Journal of Separation Science 2009 Volume 32( Issue 12) pp:2139-2145
Publication Date(Web):
DOI:10.1002/jssc.200900018
Abstract
A new solid-phase extraction coupled with magnetic carrier technology was developed for extraction of bisphenol A (BPA) and diethylstilbestrol (DES) from water samples. The SPE sorbents, functionalized magnetic nanoparticles (Fe3O4@SiO2/β-CD, core/shell), were synthesized in a two-stage system. The material was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and a vibrating sample magnetometer. SPE extraction parameters, such as volume and pH of sample, adsorption time, and desorption conditions were optimized. Under selected conditions: 250 mL of water sample, 0.1 g of sorbents and elution with methanol (3 mL with 1% acetic acid), the extraction was completed in 25 min. SPE followed by HPLC was employed to determine BPA and DES in environmental samples. The developed method provided spiked recoveries of 80–105%, relative standard deviations of less than 7%, and LOD of BPA (20.0 ng/L) and DES (23.0 ng/L), respectively. The proposed method offered easy preparation of sorbents, rapid analysis, high enrichment yields, and reliable quantitative assay.
Co-reporter:Hui Lin, Jingfeng Lan, Min Guan, Fenling Sheng, Haixia Zhang
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2009 Volume 73(Issue 5) pp:936-941
Publication Date(Web):1 September 2009
DOI:10.1016/j.saa.2009.04.025
The mechanism of interaction between mangiferin (MA) and bovine serum albumin (BSA) in aqueous solution was investigated by fluorescence spectra, synchronous fluorescence spectra, absorbance spectra and Fourier transform infrared (FT-IR) spectroscopy. The binding constants and binding sites of MA to BSA at different reaction times were calculated. And the distance between MA and BSA was estimated to be 5.20 nm based on Föster's theory. In addition, synchronous fluorescence and FT-IR measurements revealed that the secondary structures of the protein changed after the interaction of MA with BSA. As a conclusion, the interaction between the anti-diabetes Chinese medicine MA and BSA may provide some significant information for the mechanism of the traditional chinese medicine MA on the protein level to cure diabetes or other diseases.
The potential of oxidized multiwalled carbon nanotubes as a fiber coating for solid-phase microextraction of carbendazim, thiabendazole, and thiophanate-methyl from aqueous solution has been investigated, and the mechanism of adsorption has been explored. When an analytical method combining SPME with high-performance liquid chromatography was applied to real environmental water samples, recoveries of the spiked compounds was 75.7–104.5%, the linear range was 5–500 ng mL−1, the squared correlation coefficients (r2) were from 0.9978 to 0.9984, LOD were from 0.3 to 1.5 ng mL−1, and RSD were from 2.3 to 10.5%.
A simple imprinted amino-functionalized silica gel material was synthesized by combining a surface molecular imprinting technique with a sol–gel process for solid-phase extraction–high performance liquid chromatography (SPE–HPLC) determination of diethylstilbestrol (DES). Activated silica gel was used as the supporter and non-imprinted silica sorbent was synthesized without the addition of DES using the same procedure as that of DES-imprinted silica sorbent. Compared with non-imprinted polymer particles, the prepared DES-imprinted silica sorbent showed high adsorption capacity, significant selectivity, good site accessibility and fast binding kinetics for DES. The maximum static adsorption capacity of the DES-imprinted and non-imprinted silica sorbent for DES was 62.58 mg g−1 and 19.89 mg g−1, respectively. The relatively selective factor value of this DES-imprinted silica sorbent was 61.7 at the level of 50 mg L−1. And the uptake kinetics was fairly rapid so that the adsorbent equilibrium was achieved within 10 min. Furthermore, the DES-imprinted polymers were used as the sorbent in solid-phase extraction to determine DES in fish samples. The MIP–SPE–HPLC method showed higher selectivity and good recoveries higher than 87.5% (R.S.D. 11.6%).
Co-reporter:Xiao-Yan Liu, Yong-Sheng Ji, Hai-Xia Zhang, Man-Cang Liu
Journal of Chromatography A 2008 Volume 1212(1–2) pp:10-15
Publication Date(Web):28 November 2008
DOI:10.1016/j.chroma.2008.10.034
An automated on-line method for the determination of the substituted aniline compounds was developed using in-tube solid-phase microextraction coupling to high-performance liquid chromatography (HPLC). In this work, oxidized multiwalled carbon nanotubes (MWCNTs-COOH) coated on the outer surface of the fused-silica tube and inserted in the polyether ether ketone (PEEK) tubing, which was fixed directly on the six-port injection valve to substitute for the sample loop. The extraction procedure was performed by a constant flow pump frequently driving the sample solution through the PEEK tubing and the analytes were adsorbed onto MWCNTs-COOH materials when the six-port valve set to load position. After extraction, the valve switched to inject position and the extracted analytes were desorbed by mobile phase in dynamic mode. High extraction capacity was achieved for the investigated analytes and great improvement of the limits of detection was obtained in comparison with other methods. The calibration plots were linear (r2 ≥ 0.9949) over the concentration range of 1.04–104 ng mL−1 for 4-nitroaniline, 1.02–102 ng mL−1 for 2-nitroaniline, 1.68–168 ng mL−1 for 2-chloroaniline and 1.09–109 ng mL−1 for 2,4-dichloroaniline. The detection limit ranged from 0.04 ng mL−1 to 0.13 ng mL−1 (at S/N = 3). The possibility of applying the established method to water samples analysis was also studied.
Co-reporter:Huayu Huang, Cailing Yang, Haixia Zhang, Mancang Liu
Microporous and Mesoporous Materials 2008 Volume 111(1–3) pp:254-259
Publication Date(Web):15 April 2008
DOI:10.1016/j.micromeso.2007.07.038
Octyl (C8) or octadecyl (C18)-modified mesoporous SBA-15 silica molecular sieves have been prepared by adding SBA-15 silica molecular sieves to octyltrimethoxysilane or octadecyltrimethoxysilane in toluene at 100 °C, and characterized by Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), nitrogen adsorption–desorption measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). FTIR spectra shows the presence of methylene (–CH2–) and methyl (–CH3) bands on the modified SBA-15. Powder XRD data indicate the structure of modified SBA-15 with octyl or octadecyl groups still remains two-dimensional hexagonal mesostructrure. Brunauer–Emmett–Teller (BET) surface area analysis presents that surface area of octyl- and octadeyl-SBA-15 changed from 647 to 449 and 321 m2 g−1, respectively, and SEM images show the decreased size of modified SBA-15 particles. TEM images of modified materials with alkyl groups show the structures remain the same as the parent SBA-15 silica. We also have studied the adsorption capacity of the materials to phthalate esters (dimethyl and diethyl phthalate) by dynamic adsorption experiments on high performance liquid chromatography (HPLC). It is found that the modified materials can increase the adsorption of phthalate esters compared to SBA-15 particles, and the adsorption capacity increased with the increased length of alkyl chain on SBA-15. The maximum dynamic adsorption capacity for diethyl phthalate was 3.9 (C8-SBA-15) or 4.3 (C18-SBA-15) times higher than that of SBA-15 particles, respectively. The results indicate that alkyl SBA-15 particles could be used for enrichment of phthalate esters in water samples before the further analysis.
Journal of Separation Science 2007 Volume 30(Issue 18) pp:3154-3163
Publication Date(Web):15 NOV 2007
DOI:10.1002/jssc.200700160
A simple high-performance liquid chromatographic method with pre-column derivatization and fluorescence detection was developed and used for the analysis of free amino acids in islets of Langerhans; 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) served as pre-column derivatization reagent. Islets of Langerhans were separated from the pancreas of normal and obese rats, treated with pre-cooling methanol–water (80:20, v/v), and ultrasonicated to fragmentize the islets and effect deproteination. Several parameters influencing the derivatization reaction and chromatographic separation were optimized. Amino acid derivatives obtained under optimal conditions were separated on a C18 column with acetonitrile–acetate buffer as mobile phase and detected at 470 nm/540 nm (Ex/Em). Matrix effects were investigated and good linearities with correlation coefficients better than 0.9972 were obtained over a wide range of 0.42–42.11 μM for most of the amino acids. The detection limits (S/N = 3) were within the range of 6.1–51 nM. The precision of the method and recoveries were in the ranges of 1.43–10.76% (RSD%) and 85.07–108.82%, respectively. The analytical results showed that the serine content was markedly higher in normal rats than in obese rats, whereas methionine was of relatively lower content in both normal and obese rats.
Journal of Molecular Graphics and Modelling 2007 Volume 26(Issue 1) pp:246-254
Publication Date(Web):July 2007
DOI:10.1016/j.jmgm.2006.12.002
The support vector machine (SVM), which is a novel algorithm from the machine learning community, was used to develop quantitative structure–activity relationship (QSAR) models for predicting the binding affinity of 152 nonapeptides, which can bind to class I MHC HLA-A*201 molecule. Each peptide was represented by a large pool of descriptors including constitutional, topological descriptors and physical–chemical properties. The heuristic method (HM) was then used to search the descriptor space for selecting the proper ones responsible for binding affinity. The four descriptors were obtained to build linear models based on HM and nonlinear models based on SVM method. The best results are found using SVM: root mean-square (RMS) errors for training, test and whole data set were 0.383, 0.385 and 0.384, respectively. This paper allow the prediction of the binding affinity of new, untested peptides and, through the analysis of contribution of each parameter of different residue at specific position of peptidic ligands, to understand nature of the forces governing binding behavior and suggest new ideas for further synthesis of high-affinity peptides.
Co-reporter:Xiaoman Jiang, Wei Tian, Chuande Zhao, Haixia Zhang, Mancang Liu
Talanta 2007 Volume 72(Issue 1) pp:119-125
Publication Date(Web):15 April 2007
DOI:10.1016/j.talanta.2006.10.006
A novel and simple imprinted amino-functionalized silica gel material was synthesized by combining a surface molecular imprinting technique with a sol–gel process on the supporter of activated silica gel for solid-phase extraction-high performance liquid chromatography (SPE-HPLC) determination of bisphenol A (BPA). Non-imprinted silica sorbent was synthesized without the addition of BPA using the same procedure as that of BPA-imprinted silica sorbent. The BPA-imprinted silica sorbent and non-imprinted silica sorbent were characterized by FT-IR and the static adsorption experiments. The prepared BPA-imprinted silica sorbent showed high adsorption capacity, significant selectivity and good site accessibility for BPA. The maximum static adsorption capacity of the BPA-imprinted and non-imprinted silica sorbent for BPA was 68.9 and 34.0 mg g−1, respectively. The relatively selective factor value of this BPA-imprinted silica sorbent was 4.5. Furthermore, the difference of the retention characteristics of BPA on the C8 SPE column and BPA-imprinted silica SPE (MIP-SPE) was compared. The MIP-SPE-HPLC method showed higher selectivity to BPA than the traditional SPE-HPLC method. At last, the BPA-imprinted polymers were used as the sorbent in solid-phase extraction to determine BPA in water samples with satisfactory recovery higher than 99% (R.S.D. 3.7%).
Analytical and Bioanalytical Chemistry 2007 Volume 389( Issue 2) pp:355-368
Publication Date(Web):2007 September
DOI:10.1007/s00216-007-1336-6
Molecular imprinting is a technique for preparing polymeric materials that are capable of recognizing and binding the desired molecular target with a high affinity and selectivity. The materials can be applied to a wide range of target molecules, even those for which no natural binder exists or whose antibodies are difficult to raise. The imprinting of small organic molecules (e.g., pharmaceuticals, pesticides, amino acids, steroids, and sugars) is now almost routine. In this review, we pay special attention to the synthesis and application of molecular imprinted polymer (MIPs) imprinted with small organic molecules, including herbicides, pesticides, and drugs. The advantages, applications, and recent developments in small organic molecular imprinted technology are highlighted.
Traditional quantitative structure–permeability relationship (QSPR) is performed for the study of permeability coefficients of various compounds through low-density polyethylene at 21.1 °C. Descriptors calculated from the molecular structures alone were used to represent the characteristics of the compounds. The three molecular descriptors selected by the heuristic method (HM) in CODESSA were used as inputs for radial basis function neural networks (RBFNNs). The results obtained by RBFNNs were compared with those by HM. The root-mean-squared errors (RMS) for the whole data set given by HM and RBFNNs were 0.4565 and 0.3461, respectively, which shows the RBFNNs model is better than the HM model. The prediction results are in agreement with the experimental values. This paper provided a potential method for predicting the permeability coefficient in polymer science.
Co-reporter:Jianjian Zhang, Chuwen Li, Rui Zhang, Fengyuan Zhang, Wei Liu, Xiaoyan Liu, Simon Ming-Yuen Lee and Haixia Zhang
Chemical Communications 2016 - vol. 52(Issue 13) pp:NaN2682-2682
Publication Date(Web):2016/01/05
DOI:10.1039/C5CC09976E
A novel near-infrared (NIR), turn-on fluorescence probe CyR containing a phosphinate group as a recognizing moiety for the selective detection of O2˙− with a low limit of detection (LOD, 9.9 nM) was developed. CyR has good cell-membrane permeability, intracellular stability, and low cytotoxicity. In addition, we successfully applied the CyR to visualize O2˙− in live zebrafish, mouse and, for the first time, in mouse liver.
A porous hollow molecular imprinting polymer (MIPs) with ofloxacin (OFL) as template and SiO2 nanoparticle (250 nm) as sacrifice core was synthesized. Dibutyl isophthalate was used as plasticizer to strengthen the polymer shell in MIP preparation firstly, which was necessary to avoid breaking the shell. Infrared spectra and transmission electron microscopy were used to verify the successful synthesis of the hollow MIPs. The adsorption behavior of MIPs was evaluated by adsorption capacity, imprint factor and adsorption model. The MIPs could obtain the adsorption capacity of 147 mg g−1 to OFL in theory and imprint factor of 2.6 when the initial OFL concentration was 900 μg mL−1. The MIPs could adsorb not only OFL but other fluoroquinolone antibiotics (FQs), which was useful to analyze FQs together. At the same time, it hardly adsorbed other compounds with dissimilar structure. The MIPs were used as adsorbent to enrich the FQs from milk and good selectivity and enrichment ratios were obtained. Coupling with high performance liquid chromatography, the FQs in milk were determined with no more than 30 ng mL−1 of the limit of quantitation.
One molecule of zinc ion (Zn2+) could combine with two molecules of sulfadiazine (SDZ) to form a complex. Based on this concept, two experiments were performed to improve the preparation of sulfadiazine molecularly imprinted polymer materials (MIPs). One experiment used the complex of SDZ–Zn as template to replace SDZ in order to synthesize MIPs, which displayed higher selectivity and imprint factor. The second experiment used a methanol–acetic acid solution (9:1, v/v) containing 0.02 mol L−1 Zn2+ as the eluate to remove the template molecules from the synthesized MIPs, which could rapidly remove the template at 80 °C within two hours. Compared with the traditional Soxhlet extraction, the time was largely shortened.
Journal of Materials Chemistry A 2014 - vol. 2(Issue 22) pp:NaN3437-3437
Publication Date(Web):2014/03/28
DOI:10.1039/C4TB00128A
We report here a novel doxorubicin (DOX) prodrug that reduces the proportion of inactive materials and minimizes drug leak. In aqueous solutions, the resulting DOX prodrug could spontaneously form stable micelles with diameters of ∼80 nm with a DOX loading content as high as ∼40 wt%. The subsequent cytotoxicity and cell internalization behavior indicated that the resulting prodrug could show a high in vitro anticancer efficacy. We believe that this strategy could be developed to design prodrugs of various anticancer drugs and thus offer new prodrugs for cancer therapy.
In this paper, cystine- and cysteine-bonded stationary phases were synthesized and characterized by UV spectroscopy, Fourier transform infrared spectroscopy and elemental analysis which proved the successful immobilization of cystine and cysteine on the silica support. Both the new stationary phases displayed mixed-mode behavior, hydrophilic interaction chromatography (HILIC) mode and reversed-phase liquid chromatography (RPLC) mode. Retention behaviors of polar compounds on the two stationary phases were studied under different mobile phases by varying their water content, pH and ionic strength. The separation of sulfanilamide and substituted benzoic acid compounds was demonstrated on the new phases.
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