Co-reporter:Yu Yi;Canlin Lai;Yuqi Jiang;Jianfeng Mei;Hong Wang
Journal of Applied Polymer Science 2012 Volume 125( Issue S2) pp:E248-E254
Publication Date(Web):
DOI:10.1002/app.36994
Abstract
In this article, we present a novel amino-reserved magnetic chitosan microsphere (ARMCM) prepared from chitosan and Fe3O4 through inverse suspension crosslinking by formaldehyde and epichlorohydrin. The density of ARMCM was 1.47 g/mL, and the amino content was 2.44 mmol/g. The measurements data indicated that the saturation magnetization (σs) of ARMCM was 23.2 emu/g. The adsorption results showed that these magnetic chitosan microspheres had good adsorption capacity on endotoxin: the maximum absorption capacity was about 1792.1EU/g in 40 min; the endotoxin adsorption efficiency in the protein solution was close to 80% and what is more, protein adsorption efficiency was only 23.2 and 2.0%, respectively, for acidic and basic proteins. It is expected that this ARMCM will have a feasible and useful application in adsorbing endotoxin from biological products. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Guo-qing Ying, Wen-yue Xiong, Hong Wang, Yang Sun, Hua-zhang Liu
Carbohydrate Polymers 2011 Volume 83(Issue 4) pp:1787-1796
Publication Date(Web):1 February 2011
DOI:10.1016/j.carbpol.2010.10.037
Water-solubility at neutral or basic pH of chitosan was largely improved by specific attachment of carbohydrates to the 2-amino functions achieved by Maillard reaction or further reductive alkylation of Schiff bases. The characteristic physicochemical, rheological properties, and antioxidant activities of the derivatives were investigated. Experimental results indicated that the solubility of all the chitosan-saccharides before and after reducing had been greatly enhanced comparing to the native chitosan. The Schiff base typed chitosan–fructose derivative was highest at 13.2 g/L of all, and Schiff base typed chitosan derivatives existed better solubility, Ph stability and more effective scavenging activity against DPPH radical than N-alkylated chitosan derivatives. The degree of substitution (DS) of the chitosan derivatives increased with higher concentration of saccharide, increasing reaction time and temperature. The reduction of viscosity of chitosan derivatives decreased with increasing reaction time and temperature. The results suggest that the water-soluble chitosan derivatives produced through Maillard reaction may be promising commercial additive in cosmetics and food.
Co-reporter:Wen-yue Xiong, Yu Yi, Hua-zhang Liu, Hong Wang, Jin-hua Liu, Guo-qing Ying
Carbohydrate Research 2011 Volume 346(Issue 10) pp:1217-1223
Publication Date(Web):15 July 2011
DOI:10.1016/j.carres.2011.03.037
Two water-soluble chitosan (WSC) derivatives of N-succinyl-chitosan (NSCS) and N,O-succinyl-chitosan (NOSCS) with a degree of substitution (DS) that ranged form 0.28 to 0.61 were selectively synthesized by varying the molar ration of succinic anhydride and chitosan. The chemical structure and physical properties of the chitosan derivatives were characterized by FT-IR, 1H NMR, and XRD. XRD analysis showed that the derivatives were amorphous. The lysozyme enzymatic degradation results revealed that the NSCS was of higher susceptibility to lysozyme. The degradation rate and the solubility of the chitosan derivatives were strongly determined by the degree of substitution and the position of the substitution. The results of antithrombotic properties, hemolytic properties and anticoagulant properties of WSCs indicated that the blood compatibility was dramatically improved, and the carboxyl group introduced on the C-6 or C-2 hydroxyl group appeared to impact anticoagulant activity in different ways.Both N,O-succinyl-chitosan (NOSCS) and N-succinyl-chitosan (NSCS) showed magnificent blood compatibility, while the anticoagulant property indicated that NSCS was better. Enzymatic degradation assay demonstrated that the NSCS was more susceptible to lysozyme than NOSCS with similar degree of substitution.
Co-reporter:Hong Wang;Xuan Tian;GuoQing Ying
Helvetica Chimica Acta 2010 Volume 93( Issue 8) pp:1628-1633
Publication Date(Web):
DOI:10.1002/hlca.200900426
Abstract
A new nortriterpene, 2-hydroxy-3-methyl-21-oxo-12,24-dinor-D : B-friedooleana-1,3,5(10),7-tetraen-29-oic acid (1), was isolated from the root of Celastrus hypoleucus, together with the two known compounds, celastorol (2) and pristimerine (3). Their structures were elucidated on the basis of spectroscopic analyses. Compounds 1–3 exhibited in vitro significant antioxidant (against lipid peroxidation; by the TBARS method) and antitumor activities (against cancer cell lines P-388, A-549, HL-60, and BEL-7402).
Co-reporter:Lu-E Shi, Guo-Qing Ying, Zhen-Xing Tang, Jian-Shu Chen, Wen-Yue Xiong, Hong Wang
Journal of Membrane Science 2009 Volume 345(1–2) pp:217-222
Publication Date(Web):1 December 2009
DOI:10.1016/j.memsci.2009.09.001
In this paper, production of 5′-nucleotides using a free enzyme membrane reactor was presented. The enzyme membrane reactor consists in a coupling of a membrane separation process with an enzymatic reaction. Retention of substrate (RNA) and catalyst (nuclease P1) by the ultrafiltration membranes was observed. The best enzyme membrane reactor configuration was achieved with a polyethersulfone membrane of 30 kDa molecular weight cut-off, since the substrate and biocatalyst were retained with no loss of enzyme activity. Enzyme stability and optimum temperature were investigated. Other optimized operating conditions were also obtained: working temperature 65 °C, flow rate 2.0 mL/min (transmembrane pressure 0.050 MPa), and reactor volume 100 mL. The results demonstrated that enzymatic production of 5′-nucleotides from RNA was efficiently conducted by employing an ultrafiltration membrane reactor.
