Jianzhi Wang
Lanzhou University
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Publication
Featured researches published by Jianzhi Wang.
Applied Microbiology and Biotechnology | 2013
Jianzhi Wang; Guanghui Zhao; Yanfeng Li; Xiao Liu; Pingping Hou
A simple preparation process for the monodispersed pH-sensitive core-shell magnetic microspheres was carried out consisting of chitosan self-assembled on magnetic iron oxide nanoparticles. Meanwhile, glucoamylase was immobilized as a model enzyme on this carrier of Fe3O4/CS microspheres by ionic adsorption. The morphology, inner structure, and high magnetic sensitivity of the resulting magnetic chitosan microspheres were studied, respectively, with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM). Subsequently, the properties of glucoamylase immobilized on the regenerated supports were also investigated by determining storage stability, pH stability, reusability, magnetic response, and regeneration of supports. The results from characterization and determination remarkably indicated that the immobilized glucoamylase obtained presents excellent storage stability, pH stability, reusability, magnetic response, and regeneration of supports. Therefore, this kind of magnetic Fe3O4/CS microspheres with perfect monodispersity should be an ideal support for enzyme immobilization.
Chemistry-an Asian Journal | 2014
Guanghui Zhao; Jianzhi Wang; Xiaomen Peng; Yanfeng Li; Xuemei Yuan; Yingxia Ma
We report a facile fabrication of a host-metal-guest coordination-bonding system in a mesostructured Fe3O4/chitosan nanoparticle that can act as a pH-responsive drug-delivery system. The mesostructured Fe3O4/chitosan was synthesized by a solvothermal approach with iron(III) chloride hexahydrate as a precursor, ethylene glycol as a reducing agent, ammonium acetate as a porogen, and chitosan as a surface-modification agent. Subsequently, doxorubicin (DOX), acting as a model drug (guest), was loaded onto the mesostructured Fe3O4/chitosan nanoparticles, with chitosan acting as a host molecule to form the NH2-Zn(II)-DOX coordination architecture. The release of DOX can be achieved through the cleavage of coordination bonds that are sensitive to variations in external pH under weakly acidic conditions. The pH-responsive nature of the nanoparticles was confirmed by in vitro releases and cell assay tests. Furthermore, the relaxation efficiency of the nanoparticles as high-performance magnetic resonance imaging contrast agents was also investigated. Experimental results confirm that the synthesized mesostructured Fe3O4/chitosan is a smart nanovehicle for drug delivery owing to both its pH-responsive nature and relaxation efficiency.
Applied Microbiology and Biotechnology | 2011
Guanghui Zhao; Yanfeng Li; Jianzhi Wang; Hao Zhu
Magnetic carbon nanotubes (MCNTs) with necklace-like nanostructures was prepared via hydrothermal method, and hyperbranched poly(amidoamine) (PAMAM) was grafted on the surface of MCNTs on the basis of the Michael addition of methyl acrylate and the amidation of the resulting ester with a large excess of ethylenediamine (EDA), which could achieve generational growth under such uniform stepwise reactions. The terminal –NH2 groups from the dendritic PAMAM were reacted with differently functionalized groups to form functionalized MCNTs. Subsequently, enzyme was immobilized on the functionalized MCNTs through adsorption, covalent bond, and metal-ion affinity interactions. The immobilization of glucoamylase, hereby chosen as model enzyme, onto the differently functionalized MCNTs is further demonstrated and assessed based on its activity, thermal stability, as well as reusability. Besides ease in recovery by magnetic separation, the immobilized glucoamylase on functionalized MCNTs offers superior stability and reusability, without compromising the substrate specificity of free glucoamylase. Furthermore, the results indicate that the metal-chelate dendrimer offers an efficient route to immobilize enzymes via metal-ion affinity interactions. The applicability of the regenerated supports in the current study is relevant for the conjugation of other enzymes beyond glucoamylase.
Chemistry-an Asian Journal | 2013
Jianzhi Wang; Guanghui Zhao; Yanfeng Li; Xiaomeng Peng; Yan‐tao Li
Based on the characteristics of polycations of chitosan and glucoamylase, which are oppositely charged, they were successfully alternatingly deposited onto the surface of aldehyde-modified Fe3O4 nanoparticles by using a layer-by-layer ion exchange method to form magnetic carriers to construct multilayer films (designated as Fe3O4@(CS/GA)n). The (CS/GA)n film systems were endowed with the pH-dependent properties of chitosan as well as the catalytic activity of glucoamylase. The changes in weight loss and surface chemistry, morphology, and magnetic sensitivity were monitored and verified by UV/Vis spectroscopy, zeta potential, TEM, and a vibrating sample magnetometer. Subsequently, the influence of the number of bilayers, storage stability, pH, temperature, and reusability of Fe3O4@(CS/GA)5 biocatalysts on catalytic activity were investigated. The results from characterization and determination remarkably indicate that Fe3O4@(CS/GA)5 presents excellent catalytic activity, storage stability, pH stability, and reusability in comparison with free enzyme. Fe3O4@(CS/GA)5 retained >60% of its initial activity at 65 °C over 6 h; the optimum temperature and pH also increased to the ranges of 45-65 °C and 2.5-3.5, respectively, and only 27% activity was lost after 10 cycles. This new strategy simplifies the reaction protocol and improves encapsulation efficiency and catalytic activity for new potential applications in biotechnology.
Carbon | 2012
Yingxia Ma; Yanfeng Li; Guanghui Zhao; Liuqing Yang; Jianzhi Wang; Xin Shan; Xu Yan
Journal of Physical Chemistry C | 2011
Guanghui Zhao; Jianzhi Wang; Yanfeng Li; Xia Chen; Yaping Liu
Dalton Transactions | 2014
Jianzhi Wang; Guanghui Zhao; Yanfeng Li; Hao Zhu; Xiaomen Peng; Xian Gao
Biochemical Engineering Journal | 2015
Jianzhi Wang; Guanghui Zhao; Lingyun Jing; Xiaomen Peng; Yanfeng Li
Biochemical Engineering Journal | 2012
Guanghui Zhao; Jianzhi Wang; Yanfeng Li; Huayu Huang; Xia Chen
Chemical Engineering Journal | 2015
Jianzhi Wang; Guanghui Zhao; Yanfeng Li; Xiaomeng Peng; Xinyu Wang