title: Magnetic catechol-chitosan with bioinspired adhesive surface: preparation and immobilization of ω-transaminase.
abstract: The magnetic chitosan nanocomposites have been studied intensively and been used practically in various biomedical and biological applications including enzyme immobilization. However, the loading capacity and the remained activity of immobilized enzyme based on existing approaches are not satisfied. Simpler and more effective immobilization strategies are needed. Here we report a simple catechol modified protocol for preparing a novel catechol-chitosan (CCS)-iron oxide nanoparticles (IONPs) composites carrying adhesive moieties with strong surface affinity. The ω-transaminase (ω-TA) was immobilized onto this magnetic composite via nucleophilic reactions between catechol and ω-TA. Under optimal conditions, 87.5% of the available ω-TA was immobilized on the composite, yielding an enzyme loading capacity as high as 681.7 mg/g. Furthermore, the valuation of enzyme activity showed that ω-TA immobilized on CCS-IONPs displayed enhanced pH and thermal stability compared to free enzyme. Importantly, the immobilized ω-TA retained more than 50% of its initial activity after 15 repeated reaction cycles using magnetic separation and 61.5% of its initial activity after storage at 4°C in phosphate buffered saline (PBS) for 15 days. The results suggested that such adhesive magnetic composites may provide an improved platform technology for bio-macromolecules immobilized.
authors: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, China.
authors: Kefeng
authors: K
authors: Ni
authors: Xu
authors: X
authors: Zhou
authors: Li
authors: L
authors: Zhao
authors: Hualei
authors: H
authors: Wang
authors: Yuhong
authors: Y
authors: Ren
authors: Dongzhi
authors: D
authors: Wei
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D015374:Biosensing Techniques; D002396:Catechols / Q000737:chemistry*; D002448:Cell Adhesion; D048271:Chitosan / Q000737:chemistry*; D004655:Emulsions; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008280:Magnetics; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008956:Models, Chemical; D053761:Nanocomposites / Q000737:chemistry; D010316:Particle Size; D013696:Temperature; D000637:Transaminases / Q000378:metabolism*
chemical_list: D001672:Biocompatible Materials; D002396:Catechols; D004655:Emulsions; D004800:Enzymes, Immobilized; D046911:Macromolecular Substances; D048271:Chitosan; D000637:Transaminases; C034221:catechol