Co-reporter:Haijian Liu, Ming Li, Yining Xia, and Xueqin Ren
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 1) pp:
Publication Date(Web):December 14, 2016
DOI:10.1021/acsami.6b11920
In this work, a novel approach for simple and sensitive determination of alkaline phosphatase (ALP) is developed on the basis of an inner filter effect of p-nitrophenylphosphate (PNPP) on the fluorescence of gold nanoclusters (AuNCs). AuNCs with a high quantum yield of 12% were synthesized by one-pot strategy and were directly applied as fluorescent substance. When AuNCs were mixed with PNPP, the fluorescence of the AuNCs was remarkably quenched or was decreased via the inner filter effect since the absorption spectrum of PNPP overlaps well with the excitation spectrum of the AuNCs. While in the presence of ALP, PNPP was catalytically hydrolyzed into p-nitrophenol, which has different absorption characteristics from those of PNPP, resulting in the recovery of the AuNCs fluorescence. Thus, a novel “turn-on” fluorescent sensor for detecting ALP was established with a detection limit as low as 0.002 U/L (signal-to-noise ratio of 3). The turn-on fluorescent sensor exhibits many merits such as high sensitivity, excellent selectivity, and high signal output because of the low background signals. In addition, the developed sensing method was successfully applied to investigate ALP inhibitors and ALP determination in serum samples. A good linear relationship was obtained in the range from 0.02 to 50 U/L, and satisfactory recoveries at four spiking levels of ALP ranged from 95% to 106% with precision below 5%. The very simple sensing approach proposed here should promote the development of fluorescence turn-on chemosensors for chemo/biodetection.Keywords: alkaline phosphatase; fluorescence; gold nanoclusters; inner filter effect; turn-on;
Co-reporter:Haijian Liu, Ming Li, Linye Jiang, Feng Shen, Yufeng Hu, Xueqin Ren
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 Volume 173() pp:105-113
Publication Date(Web):15 February 2017
DOI:10.1016/j.saa.2016.08.057
•A simple, sensitive and novel fluorescent detection method for arginine was proposed.•This method has the merits of simplicity, rapidity, and easy operation.•The detection limit of this method was as low as 5.6 μg L− 1.•This method was successfully applied to the detection of arginine in blood plasma samples.Arginine plays an important role in many biological functions, whose detection is very significant. Herein, a sensitive, simple and cost-effective fluorescent method for the detection of arginine has been developed based on the inner filter effect (IFE) of citrate-stabilized gold nanoparticles (AuNPs) on the fluorescence of thioglycolic acid-capped CdTe quantum dots (QDs). When citrate-stabilized AuNPs were mixed with thioglycolic acid-capped CdTe QDs, the fluorescence of CdTe QDs was significantly quenched by AuNPs via the IFE. With the presence of arginine, arginine could induce the aggregation and corresponding absorption spectra change of AuNPs, which then IFE-decreased fluorescence could gradually recover with increasing amounts of arginine, achieving fluorescence “turn on” sensing for arginine. The detection mechanism is clearly illustrated and various experimental conditions were also optimized. Under the optimum conditions, a decent linear relationship was obtained in the range from 16 to 121 μg L− 1 and the limit of detection was 5.6 μg L− 1. And satisfactory results were achieved in arginine analysis using arginine injection, compound amino acid injection, even blood plasma as samples. Therefore, the present assay showed various merits, such as simplicity, low cost, high sensitivity and selectivity, making it promising for sensing arginine in biological samples.
Co-reporter:Linye Jiang, Haijian Liu, Ming Li, Yue Xing and Xueqin Ren
Analytical Methods 2016 vol. 8(Issue 10) pp:2226-2232
Publication Date(Web):29 Jan 2016
DOI:10.1039/C5AY03160E
We tested a simple and economical approach to synthesize CdTe quantum dots (QDs). We then developed a MIP-capped CdTe QD fluorescent sensor by anchoring a molecularly imprinted polymer (MIP) layer on the surface of CdTe QDs using 3-aminopropyltriethoxysilane as the functional monomer and tetramethoxysilane as the cross-linker via a surface molecular imprinting process. The sensor possessed the sensitivity of CdTe QDs, the selectivity of the molecular imprinting technique, and a nearly spherical morphology. The fluorescence of the MIP-capped CdTe QDs can be efficiently quenched when the template 4-nitrophenol (4-NP) rebinds to the binding sites, as a result of the charge transfer from QDs (donor) to 4-NP (acceptor). MIP-capped CdTe QDs generated a significantly reduced fluorescence intensity within the initial 12 min of binding 4-NP. Under optimized conditions, the sensor presented a satisfactory linearity with 4-NP concentrations in the range of 1–30 μM, and the detection limit was 40 nM. The sensor also successfully detected trace amounts of 4-NP in water samples, and the recovery of 4-NP in three spiked samples ranged from 95.1% to 98.1% with relative standard deviations below 4.3%. The results provide an alternative method for the development of sensors for the rapid recognition and determination of 4-NP in water samples.
Co-reporter:Ming Li;Feng Shen;Zhe Zhang
Chromatographia 2016 Volume 79( Issue 1-2) pp:71-78
Publication Date(Web):2016 January
DOI:10.1007/s10337-015-2998-4
In this work, a fluorescent, molecularly imprinted polymer sensor was developed for the rapid and direct sensing of trace alachlor. 2-Acrylamide-6-methoxybenzothiazole, synthesized via a simple one-step reaction with 2-amino-6-methoxybenzothiazole and acryloyl chloride, was used as both fluorescent reporter and functional monomer to prepare an alachlor-imprinted polymer. In this way, binding events produced physically detectable fluorescence signals, and the alachlor could therefore be quantified directly without any further treatment. Binding experiments demonstrated that the fluorescence intensity of the resultant polymer decreased linearly with increases in the concentration of alachlor, in the range of 1–150 μM, and with a detection limit of 0.5 μM. In addition, the fluorescent sensor exhibited significant selectivity toward alachlor over its potentially competing molecules of S-metolachlor, cyanazine, and cypermethrin. Finally, the proposed method was successfully applied for the determination of trace alachlor in corn seed samples, with excellent recoveries ranging from 95.58 to 103.83 %. The developed method shows great potential for the determination of residual alachlor in real samples.
Co-reporter:Feng Shen, Qingxi Zhang and Xueqin Ren
Chemical Communications 2015 vol. 51(Issue 1) pp:183-186
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4CC04739G
A novel zwitterion acting as both a functional monomer and a crosslinker with the protein-resistant ability concomitantly was synthesized for preparing water compatible diclofenac imprinted polymers. This new imprinted polymer showed high imprinting efficiency for template and strong anti-protein adsorption in aqueous medium.
Co-reporter:Yue Xing, Yufeng Hu, Lun Jiang, Zideng Gao, Zhenhang Chen, Zhongzhou Chen, and Xueqin Ren
Crystal Growth & Design 2015 Volume 15(Issue 10) pp:4932-4937
Publication Date(Web):August 18, 2015
DOI:10.1021/acs.cgd.5b00819
Zwitterion additives have been used in protein crystallization to prevent the appearance of crystal clusters. Herein, we have developed a novel approach for the immobilization of zwitterion onto molecularly imprinted polymers (MIPs) to yield high-quality single protein crystals. For lysozyme, trypsin, catalase, proteinase K, concanavalin A-type IV, and thaumatin, simply adding the selected zwitterion (3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl) ammonium hydroxide) into the free solution, the crystallization was improved. When further using the zwitterion-immobilized molecularly imprinted polymers (ziMIPs) developed in the current study, the formation of higher quality crystals was facilitated in a shorter time compared with regular MIPs and traditional crystallization trials. Most notably, concanavalin A-type IV, which has nonunique ordered assembly, gave only the form IV structure with higher resolution in the presence of ziMIPs, justifying the superior function of ziMIPs for the ordered assembly of protein molecules. Thus, the ziMIPs could be widely used in protein crystallization.
Co-reporter:Yu Wang, Zideng Gao, Feng Shen, Yang Li, Sainan Zhang, Xueqin Ren, and Shuwen Hu
Journal of Agricultural and Food Chemistry 2015 Volume 63(Issue 21) pp:5196-5204
Publication Date(Web):May 6, 2015
DOI:10.1021/acs.jafc.5b01378
Chlorpyrifos’ application and delivery to the target substrate needs to be controlled to improve its use. Herein, poly(butyl acrylate-co-styrene) (poly(BA/St)) and poly(BA/St/ethylene glycol dimethacrylate (EGDMA)) microcapsules loaded with chlorpyrifos as a slow release formulation were prepared by emulsion polymerization. The effects of structural characteristics on the chlorpyrifos microcapsule particle size, entrapment rate (ER), pesticide loading (PL), and release behaviors in ethyl alcohol were investigated. Fourier transform infrared and thermogravimetric analysis confirmed the successful entrapment of chlorpyrifos. The ER and PL varied with the BA/St monomer ratio, chlorpyrifos/monomer core-to-shell ratio, and EGDMA cross-linker content with consequence that suitable PL was estimated to be smaller than 3.09% and the highest ER was observed as 96.74%. The microcapsule particle size (88.36–101.8 nm) remained mostly constant. The extent of sustainable release decreased with increasing content of BA, St, or chlorpyrifos in the oil phase. Specifically, an adequate degree of cross-linking with EGMDA (0.5–2.5%) increased the extent of sustainable release considerably. However, higher levels of cross-linking with EGDMA (5–10%) reduced the extent of sustainable release. Chlorpyrifos release from specific microcapsules (monomer ratio 1:2 with 0.5% EGDMA or 5 g chlopyrifos) tended to be a diffusion-controlled process, while for others, the kinetics probably indicated the initial rupture release.
Co-reporter:Zhe Zhang, Ming Li, Feng Shen and Xueqin Ren
Analytical Methods 2015 vol. 7(Issue 14) pp:5794-5800
Publication Date(Web):03 Jun 2015
DOI:10.1039/C5AY01023C
Novel fluorescent, molecularly imprinted polymers (MIPs) were synthesized to detect sulfadiazine (SDz), an antibiotic used in animals that produce food for human consumption. Radical polymerization between a novel fluorescent monomer 7-acryloxy-4-methylcoumarin, ethylene glycol dimethacrylate and methacrylic acid, in the presence of SDz as a molecular template, afforded the target MIPs. The photoluminescence properties of these MIPs were studied and found to exhibit stable, enhanced fluorescence emission. The fluorescence emission of both the MIPs and non-imprinted polymers (NIPs) was quenched in the presence of SDz and similar analogues. Significantly, the MIPs were more sensitive than the NIPs for the SDz analyte, confirming that molecular imprinting imparted selectivity. The fluorescence quenching ratio of the MIPs exhibited a linear decrease with increasing concentrations of SDz in the range of 1.0–40 μmol L−1 with a detection limit of 0.48 μmol L−1. Importantly, the MIPs proved successful in determining SDz concentrations in spiked milk samples and showed superior recovery from 85.73% to 101.37%.
Co-reporter:Yufeng Hu, Lin Xie, Yahai Lu, and Xueqin Ren
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 22) pp:20550
Publication Date(Web):October 31, 2014
DOI:10.1021/am506223k
Studies on methanotrophs utilizing methane as sole source of carbon and energy are meaningful for governing global warming; although, the isolation of methanotrophs from nature is challenging. Here, surface imprinted polyurethane films were fabricated to selectively capture living methanotrophs from paddy soil. Two tracks of molecularly imprinted film based on polyurethane (PU-MIF1 and PU-MIF2) were imprinted using type I or II methanotrophs as template, respectively, and then reacted with polyethylene glycol, castor oil, and hexamethylene diisocyanate. Results demonstrated these PU-MIFs hold low water absorption rate and superior biocompatibility, which was highly demanded for maintaining cell viability. Superior selectivity and affinity of PU-MIFs toward their cognate methanotroph cells was observed by fluorescent microscopy. Atomic force microscopy revealed the adhesion force of PU-MIFs with its cognate cells was much stronger in comparison with noncognate ones. Using the as-prepared PU-MIFs, within 30 min, methanotroph cells could be separated from rice paddy efficiently. Therefore, the PU-MIFs might be used as an efficient approach for cell sorting from environmental samples.Keywords: cell isolation; methanotroph; molecularly imprinted film; polyurethane; viability
Co-reporter:Feng Shen and Xueqin Ren
RSC Advances 2014 vol. 4(Issue 25) pp:13123-13125
Publication Date(Web):28 Feb 2014
DOI:10.1039/C4RA00424H
Covalently mannose imprinted polymers were prepared by a simple one-pot method in aqueous medium for the first time. This new imprinted polymer showed high imprinting efficiency and fast kinetic binding for template in the water phase.
Co-reporter:Xiao Zhang, Feng Shen, Zhe Zhang, Yue Xing and Xueqin Ren
Analytical Methods 2014 vol. 6(Issue 23) pp:9483-9489
Publication Date(Web):08 Oct 2014
DOI:10.1039/C4AY01651C
A new bifunctional monomer acting as both a cross-linker and a functional monomer was synthesized and applied in the preparation of water-compatible naproxen sodium imprinted polymers. The bifunctional feature was endowed by including quaternary ammonium as a cationic functionalized group in the middle for reaction with anionic molecules, together with two reactive vinyl groups on both ends for polymerization. The monomer owned superb water solubility, which was particularly conducive for preparing MIP in aqueous solution. Taking advantage of this double functionalized monomer, naproxen sodium imprinted polymers were manufactured in aqueous media. A small quantity of the new monomer embedded in the polymers demonstrated a significant influence on the binding performance of the MIPs. Results of rebinding experiments revealed that in water, the bifunctional monomer based MIPs exhibited much higher adsorption capacity (34.4 mg g−1) than acrylamide and 2-vinyl pyridine based MIPs (8.6 mg g−1 and 8.9 mg g−1, respectively). The maximum imprinting efficiency of the MIP reached 9.1. In addition, recoveries of template spiked in distilled water, drinking water and waste river water were 85%, 84% and 70%, respectively. We believe that the new bifunctional monomer can be extended to prepare more water compatible MIPs.
Co-reporter:Quishui Li, Feng Shen, Xiao Zhang, Yufeng Hu, Qingxi Zhang, Lin Xu, Xueqin Ren
Analytica Chimica Acta 2013 Volume 795() pp:82-87
Publication Date(Web):17 September 2013
DOI:10.1016/j.aca.2013.07.040
•MIP for recognition of tyrosine phosphopeptides in aqueous media was prepared by epitope approach.•The MIPs demonstrated high adsorption capacity and selectivity for phenylphosphonic acid.•The MIP showed clear preference for tyrosine phosphopeptides over other peptides.The tyrosine phosphorylation of proteins plays a vital role in signal transduction pathways. The highly selective enrichment of tyrosine phosphopeptides remains a significant challenge in this area of research because of the low levels of tyrosine phosphorylation in cells. Herein, we report the development of a novel molecularly imprinted polymer (MIP)-based method for the recognition of tyrosine phosphopeptides in aqueous media using an epitope approach. Phenylphosphonic acid, which has been regarded the “epitope” of phosphotyrosine, was used as a template, and commercially available zinc acrylate was used as a functional monomer to prepare the MIP. The one-pot synthetic process was simple, efficient, and the resulting MIPs were low-cost, robust, and recyclable. The MIP demonstrated significant higher levels of adsorption capacity and selectivity for phenylphosphonic acid than the non-imprinting polymer (NIP) over its structural analog benzoic acid. The MIP was also used as a molecular receptor to recognize tyrosine phosphopeptides in aqueous media, and showed a clear preference for tyrosine phosphopeptides over interfering serine peptides compared to TiO2. These results revealed the feasibility of the use of MIPs to effectively mimic the epitope approach, and provided a promising alternative to the immunoaffinity techniques commonly used for capturing tyrosine phosphopeptides.
Co-reporter:Chao Chen, Shuming Tao, Xiaoyun Qiu, Xueqin Ren, Shuwen Hu
Carbohydrate Polymers 2013 Volume 91(Issue 1) pp:269-276
Publication Date(Web):2 January 2013
DOI:10.1016/j.carbpol.2012.08.042
A series of N-phthaloyl acylated chitosan membranes with controlled permeability were synthesized by the regioselective protection of the chitosan amino groups as the corresponding phthalimides followed by reaction with the long-chain dodecanoyl chloride. Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H NMR) analysis suggested that the degree of substitution (DS) ranged from 2.8 to 3.6. Contact angles, water retention values and mechanical examinations demonstrated that the hydrophobicity and mechanical properties of the membranes were all improved significantly following the modifications, together with their solubility in many organic solvents. Thermal weight change analysis demonstrated that a higher DS provided enhanced thermal properties. The controlled permeability of the membranes was determined by measuring the diffusion of urea, and the amount of urea released decreased significantly with increasing DS. The comprehensive properties of the membranes could be tuned by regulating their DS values as required.Highlights► Acylated chitosan was synthesized using N-phthaloyl chitosan as an intermediate. ► The solubility of acylated chitosan has been improved significantly. ► The hydrophobicity of acylated chitosan has been improved significantly. ► The permeability of acylated chitosan membranes could be tuned by adjusting DS.
Co-reporter:Lin Xu, Yufeng Hu, Feng Shen, Qiushui Li, Xueqin Ren
Journal of Chromatography A 2013 Volume 1293() pp:85-91
Publication Date(Web):7 June 2013
DOI:10.1016/j.chroma.2013.04.013
•We developed an epitope imprinting approach for pTyr peptide capture by MIPs.•PPA, a characteristic component of phenylphosphate group was used as template.•MIPs showed good selectivity and clear preference for pTyr peptide over pSer.•MIPs performed much more capacity (1.5-fold) to TiO2 for pTyr peptide recognition.•After three reuse cycles, there were still 94% of adsorption capacity retained.Protein phosphorylation on tyrosine residues is an important cell signaling mechanism that regulates embryo development, cell growth, differentiation and migration. Here, we developed an epitope imprinting approach to selectively enrich tyrosine-phosphorylated (pTyr) peptides using molecularly imprinted polymers (MIPs). An artificial receptor based on MIPs was prepared by precipitation polymerization using phenylphosphonic acid (PPA) as a template, Ti4+-immobilized ethylene glycol methacrylate phosphate as functional monomer, poly(ethylene glycol) diacrylate and N,N′-methylenebisacrylamide as crosslinkers, and deionized water as a porogen. The performance of MIPs was first evaluated by rebinding PPA, and then a competition experiment was conducted to assess the selectivity and specificity for PPA when mixed with benzoic acid, a structural analog. The imprinting factor of the MIPs was up to 2.04, compared with just 0.24 for benzoic acid. The selectivity and capacity of the MIPs for pTyr peptides from a mixture of peptides were considerably higher than that of commercial TiO2. And after six rebinding cycles, there were still 95% adsorption efficiency retained. Finally, MIPs were used for pTyr enrichment from a complex sample containing pTyr peptide and tryptic digestion of β-casein, where it demonstrated a clear preference for the pTyr peptide over ones containing phosphorylated serine.
Co-reporter:Feng Shen;Yufeng Hu;Ping Guan
Journal of Separation Science 2013 Volume 36( Issue 3) pp:540-547
Publication Date(Web):
DOI:10.1002/jssc.201200821
A facile two-step method for preparing chitosan-based immobilized metal ion affinity chromatography was developed. First, chitosan was phosphorylated by esterification with phosphoric acid, and then titanium was chelated onto the phosphorylated chitosan. The obtained chitosan-based titanium immobilized metal ion affinity chromatography was ultrafine microparticles and had good dispersibility in acidic buffer. The selectivity and sensitivity were evaluated by phosphopeptide enrichment of mixtures of α-casein and bovine serum albumin. The enriched peptides were analyzed by mass spectrum. Enrichment protocols were optimized and the optimum-loading buffer was 80% acetonitrile with 1% trifluoroacetic acid. With α-casein concentration as low as 2 pmol, 12 phosphopeptides were detected with considerably high intensity from the digest mixtures of α-casein and bovine serum albumin with molar ratio of 1:200. The microparticles was also applied in real biological samples, 29 phosphoproteins containing 40 phosphorylated sites were identified from salt-stressed Arabidopsis thaliana leaves.
Co-reporter:Yufeng Hu;Shuangxi Guo;Hongbo Ma;Ning Ye
Journal of Separation Science 2013 Volume 36( Issue 21-22) pp:3563-3570
Publication Date(Web):
DOI:10.1002/jssc.201300622
Despite recent advances in phosphoproteomics, an efficient and simple enrichment protocol is still a challenge and of high demand aiming at large-scale plant phosphoproteomics studies. Here, we developed a novel loading buffer system for synthesized immobilized metal affinity chromatography material targeting plant samples, which was prepared by a simple one-step esterification between polyvinyl alcohol and phosphoric acid and then was subjected to immobilize Ti4+. SEM and Fourier transform IR spectroscopy were used to assure the synthesis protocol of the polyvinyl alcohol-based Ti4+ immobilized material, and the specific surface areas and pore volumes of the polymers were measured. The selectivity for phosphopeptide enrichment from α-casein was improved by optimizing the pH and components of the loading buffer. By using potassium hydrogen phthalate/hydrochloric acid with pH at 2.50 as the loading buffer, 19 phosphopeptides with high intensity were identified. The final optimized protocol was adapted to salt-stressed maize leaves for phosphoproteome analysis. A total of 57 phosphopeptides containing 59 phosphorylated sites from 50 phosphoproteins were identified in salt-stressed maize leaf. The research was meaningful to obtain much more information about phosphoproteins leading to the comprehension of salt resistance and salt-inducible phosphorylated processes of maize leaves.
Co-reporter:Xiaoyun Qiu;Dacai Zhu;Shuming Tao;Chao Chen;Shuwen Hu
Journal of Applied Polymer Science 2013 Volume 129( Issue 2) pp:559-567
Publication Date(Web):
DOI:10.1002/app.38656
Abstract
Esters derived from 1-naphthylacetic acid (NAA) and polyacrylate were synthesized and a dual controlled-release formulation was developed by coating fertilizers with these esters. FT-IR, 1H NMR, TGA, and DSC were used to characterize the synthesized polymers, and the mechanical properties were also tested. Urea granules were coated with NAA esters, and the release rates of urea from the coated granules in water were measured. NAA release from the esters was performed in different buffer solutions and in soil. The results showed that the coated fertilizers were able to release urea in a controlled pattern and that NAA could be slowly released from membranes of the esters in both buffer solutions and in soil through hydrolysis. The coated fertilizer's availability could last more than 28 days and that of NAA could last more than 12 months, which suggested that the prepared CRF possessed dual controlled-release of urea and NAA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Xiaoyun Qiu, Shuming Tao, Xueqin Ren, Shuwen Hu
Carbohydrate Polymers 2012 Volume 88(Issue 4) pp:1272-1280
Publication Date(Web):16 May 2012
DOI:10.1016/j.carbpol.2012.02.007
Microcrystalline cellulose was modified by crosslinking with toluene diisocyanate under homogeneous phase in N,N-dimethylacetamide/LiCl solvent system. Modified cellulose films were prepared by solution casting method and their hydrophobicity, thermal stability, permeability, and degradability were characterized. The hydrophobicity, thermal stability, and mechanical properties of the films were improved by crosslinking according to the comprehensive results. The permeation rate of urea dropped rapidly from 107.7 mg/(cm2 h) to 0.88 mg/(cm2 h) with toluene diisocyanate/microcrystalline cellulose (TDI/MCC) increasing. Biodegradability of the films was examined in both controlled compost extract and natural cultivated soil. Comprehensive results including CO2 emission, scanning electron microscope (SEM) and attenuated total reflection infrared (ATR-IR) demonstrated that the films were biodegradable and the biodegradability decreased with TDI/MCC increasing. The results indicated that both permeation capability and biodegradability of the cellulose films can be optimized based on requirements.Highlights► Cellulose films were prepared by crosslinking with toluene diisocyanate in DMAc/LiCl solvent system. ► The permeation rates of these films were controllable by adjusting crosslinking density. ► Cellulose films were controllable biodegradable by adjusting crosslinking density. ► Biodegradability was determined by the method of ISO 14852-1999 and burying in natural cultivated soil.
Co-reporter:Feng Shen, Yufeng Hu, Ping Guan, Xueqin Ren
Journal of Chromatography B 2012 Volume 902() pp:108-115
Publication Date(Web):1 August 2012
DOI:10.1016/j.jchromb.2012.06.033
In this study, a novel immobilized metal ion affinity chromatography (IMAC) material for phosphopeptide enrichment was prepared based on modified cellulose and was applied in rice phosphoproteome analysis. Firstly, cellulose was modified with phosphoric acid via esterification, and then Ti4+ was chelated onto the phosphorylated cellulose. The synthesized materials were ultrafine powders and had good dispersibility in acidic buffer, and as supporting matrix, phosphorylated cellulose exhibited good biocompatibility and chemical stability. Enrichment conditions were optimized and the optimum loading buffer was 40% acetonitrile (ACN) with 6% trifluoroacetic acid (TFA). Finally, the Ti4+-phosphate functionalized cellulose was submitted to phosphopeptides enrichment prior to mass spectrometry (MS). For α-casein lysates, 14 phosphopeptides were detected with high intensities even though the sample concentration was as low as 2 pmol. Besides, 15 phosphopeptides were still identified by using the digest mixture of α-casein and bovine serum albumin with molar ratio of 1:100, which demonstrated high specificity and sensitivity for phosphopeptides enrichment. 19 phosphoproteins were identified from 200 μg of salt-free rice leaf protein lysates, while 30 phosphoproteins were identified from salt-stressed rice leaf protein lysates, and most of these proteins were related to the biological processes in response to abiotic stimulus.Highlights► A novel IMAC material for phosphopeptides capture was prepared based on cellulose. ► 14 phosphopeptides were identified from 2 pmol α-casein lysates. ► 15 phosphopeptides were identified from α-casein and BSA digests mixture (1:100). ► The material was applied successfully in rice phosphoproteome analysis.
Co-reporter:Shuming Tao, Ran Pang, Chao Chen, Xueqin Ren, Shuwen Hu
Carbohydrate Polymers 2012 88(4) pp: 1189-1194
Publication Date(Web):
DOI:10.1016/j.carbpol.2012.01.076
Co-reporter:Shuming Tao;Jun Liu;Kemo Jin;Xiaoyun Qiu;Yuan Zhang;Shuwen Hu
Journal of Applied Polymer Science 2011 Volume 120( Issue 4) pp:2103-2111
Publication Date(Web):
DOI:10.1002/app.33366
Abstract
Triple polymer coated with controlled-release water retention fertilizer (TCWF) and enhanced mechanical property was developed by coating polyethylene (first layer), poly (acrylic acid-co-acrylamide) superabsorbent (second layer), and poly (butyl methacrylate) (third layer) consecutively on the granule core urea in the fluidized-bed coater. The inner layer possessed controlled-release property, the middle layer had water absorbent characteristic, and the thin outer layer aimed to protect the fragile layer of the superabsorbent. The relationship between the thickness of coating layer and the nutrient releasing properties was established. The effects of polymerization parameters on the water absorbency of the superabsorbent were studied and optimized as well. The nutrients release behaviors of this triple-coated urea in both water and soil were investigated and compared. The results showed that TCWF not only performed as a good controlled-release fertilizer but also had excellent water retention capacity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Hongbo Ma;Yufeng Hu;Futong Yu;Fusuo Zhang
Chromatographia 2011 Volume 73( Issue 7-8) pp:681-690
Publication Date(Web):2011 April
DOI:10.1007/s10337-011-1961-2
In the present work, six nonionic block copolymer surfactants consisting of poly(ethylene glycol) (PEG), polyethylene (PE), and poly(propylene glycol) (PPG) were exploited to extract total proteins from maize (Zea mays L.) roots within a water–organic solvent system. After the treatment, proteins were partitioned into aqueous phase, interphase, and organic phase. The total yield was increased by up to 30% after adding PE-PEG block polymer surfactant compared with control. Two-dimensional electrophoresis (2-DE) was further used to evaluate proteins in water phase and interphase; the results revealed that the spot numbers and density were all improved, and well-focused electrophoretic patterns were achieved with higher density and without excess Joule heating problem after adding nonionic block polymer surfactants. Among the six investigated block polymers, PE-PEG extracted the largest amount of proteins.
Co-reporter:Weili Zhou;Yuan Zhang;Kemo Jin;Xiaoyun Qiu;Shuwen Hu;Fusuo Zhang
Journal of Applied Polymer Science 2009 Volume 114( Issue 5) pp:2828-2836
Publication Date(Web):
DOI:10.1002/app.30776
Abstract
We have synthesized series of superabsorbent polymers (SAPs) by solution free radical polymerization of acrylic acid (AA), acrylamide (AM) with different functional monomers (FM). Three functional monomers including zwitterionic monomer [3-(methacryloylamino) propyl] dimethyl (3-sulfopropyl) ammonium (MPDSA), cationic monomer (3-acrylamidopropyl) trimethylammonium chloride (APTAC) and anionic monomer 2-acrylamidoglycolic acid monohydrate (AGAM) were selected to provide different charged groups on the superabsorbents. The effect of reaction parameters, such as degree of neutralization, content of initiator and crosslinker on the swelling capacity were assessed. The water absorbency of the superabsorbent were characterized in the distilled water, 0.9 wt % NaCl solution and the mixed solution containing 60 mg L−1 CaCl2 and 30 mg L−1 MgCl2, respectively. In addition, the swelling rate and water retention capacity in the soil were also investigated. Finally, the mechanism of different absorbency induced by the variety kinds of functional monomers was studied by XPS and FTIR, and tentative interpretation was presented as well. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Ming Li, Haijian Liu, Xueqin Ren
Biosensors and Bioelectronics (15 March 2017) Volume 89(Part 2) pp:899-905
Publication Date(Web):15 March 2017
DOI:10.1016/j.bios.2016.09.101
Co-reporter:Feng Shen, Qingxi Zhang and Xueqin Ren
Chemical Communications 2015 - vol. 51(Issue 1) pp:NaN186-186
Publication Date(Web):2014/10/17
DOI:10.1039/C4CC04739G
A novel zwitterion acting as both a functional monomer and a crosslinker with the protein-resistant ability concomitantly was synthesized for preparing water compatible diclofenac imprinted polymers. This new imprinted polymer showed high imprinting efficiency for template and strong anti-protein adsorption in aqueous medium.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 23) pp:
Publication Date(Web):
DOI:10.1039/C4AY01651C
A new bifunctional monomer acting as both a cross-linker and a functional monomer was synthesized and applied in the preparation of water-compatible naproxen sodium imprinted polymers. The bifunctional feature was endowed by including quaternary ammonium as a cationic functionalized group in the middle for reaction with anionic molecules, together with two reactive vinyl groups on both ends for polymerization. The monomer owned superb water solubility, which was particularly conducive for preparing MIP in aqueous solution. Taking advantage of this double functionalized monomer, naproxen sodium imprinted polymers were manufactured in aqueous media. A small quantity of the new monomer embedded in the polymers demonstrated a significant influence on the binding performance of the MIPs. Results of rebinding experiments revealed that in water, the bifunctional monomer based MIPs exhibited much higher adsorption capacity (34.4 mg g−1) than acrylamide and 2-vinyl pyridine based MIPs (8.6 mg g−1 and 8.9 mg g−1, respectively). The maximum imprinting efficiency of the MIP reached 9.1. In addition, recoveries of template spiked in distilled water, drinking water and waste river water were 85%, 84% and 70%, respectively. We believe that the new bifunctional monomer can be extended to prepare more water compatible MIPs.
Co-reporter:Zhe Zhang;Ming Li;Feng Shen
Analytical Methods (2009-Present) 2015 - vol. 7(Issue 14) pp:NaN5800-5800
Publication Date(Web):2015/07/09
DOI:10.1039/C5AY01023C
Novel fluorescent, molecularly imprinted polymers (MIPs) were synthesized to detect sulfadiazine (SDz), an antibiotic used in animals that produce food for human consumption. Radical polymerization between a novel fluorescent monomer 7-acryloxy-4-methylcoumarin, ethylene glycol dimethacrylate and methacrylic acid, in the presence of SDz as a molecular template, afforded the target MIPs. The photoluminescence properties of these MIPs were studied and found to exhibit stable, enhanced fluorescence emission. The fluorescence emission of both the MIPs and non-imprinted polymers (NIPs) was quenched in the presence of SDz and similar analogues. Significantly, the MIPs were more sensitive than the NIPs for the SDz analyte, confirming that molecular imprinting imparted selectivity. The fluorescence quenching ratio of the MIPs exhibited a linear decrease with increasing concentrations of SDz in the range of 1.0–40 μmol L−1 with a detection limit of 0.48 μmol L−1. Importantly, the MIPs proved successful in determining SDz concentrations in spiked milk samples and showed superior recovery from 85.73% to 101.37%.
