壳聚糖-g-N-羧甲基-2-硫代-4,5-2H咪唑啉酮-多壁碳纳米管复合物固定漆酶基化学传感器的性能

通过壳聚糖-g-N-羧甲基-2-硫代-4,5-2H咪唑啉酮(CTS-g-N-CSIDZ)非共价功能化多壁碳纳米管(MWCNTs)的方式制备固定漆酶载体,该复合物载体主要通过物理吸附和漆酶活性中心与载体上配体之间的配位作用来固定漆酶,较大程度地保持了游离漆酶活性位原始构象.将固定了漆酶的复合物附着在裸玻碳电极上便构筑了复合物固定漆酶修饰玻碳电极.在以分光光度法测定了这种复合物载体对漆酶的担载量、固定漆酶比活力、稳定性、重复使用性及其催化2,6-二甲氧基苯酚(DMP)氧化动力学参数的基础上,还对基于此种复合物固定漆酶修饰玻碳电极作为化学传感器(以DMP作为底物)的性能进行了研究.结果表明,该复合物具有较高的固酶担载量(81.7 mg/g)和固定漆酶比活力(1.33 U/mg)；而作为电化学传感器的复合物固定漆酶修饰玻碳电极对底物DMP具有较高的亲和力(对DMP的米氏常数KM是0.0918 mmol/L),较高的灵敏度( 3680 mA· L/mol),较低的检测限(3.3×10-4 mmol/L),较高的响应选择性,良好的重现性、重复使用性和长期稳定性.这种漆酶基电极有望用作电流型特定结构的酚类传感器.

Function of Chemical Sensor Based on the Immobilization of Laccase on the Composite of Chitosan-g-N-carboxymethyl-2-sulfo-4,5-2H Imidazolinone and Multiwall Carbon Nanotubes

The matrix for laccase immobilization consisting of chitosan-g-N-carboxymethyl-2-sulfo-4,5-2H imidazolinone(CTS-g-N-CSIDZ) and multiwall carbon nanotubes(MWCNTs) was prepared through MWCNTs non-covalently functionalized with CTS-g-N-CSIDZ.Laccase immobilization on the composite carrier was achieved mainly by physical adsorption together with active centers in laccase complexing with ligands on the carrier and therefore the immobilized laccase could retain its original conformation of active centre to a great extent.On the glassy carbon electrode modified by the composite with adsorbed laccase was fabricated by a layer of composite composed with entrapped laccase attached to the surface of bare electrode.On the basis of determinoffing the loading of the composite matrix towards laccase,specific activity of immobilized laccase,stability,reusability and catalytic 2,6-dimethoxyphenol(DMP) oxidization dynamic parameters of the immobilized laccase on the composite matrix,function of this chemical sensor based on the electrode modified with the composite which accommodated laccase were examined(DMP as substrate).Results indicated this composite matrix for laccase entrapment had superiority of high enzyme loading amount(81.7 mg/g),improved laccase specific activity in immobilized state(1.33 U/mg).While the entrapped laccase in composite modified electrode as electrochemical sensor showed favorable affinity towards its substrate:DMP(Michaelis-Menten constant KM is 0.0918 mmol/L),relatively higher sensitivity to DMP(3680 mA·L/mol),lower detection limit for DMP(3.3×10-4 mmol/L),its relatively higher responsible selectivity,favorable reproducibility,reusability and excellent long-term stability were obtained.Such advantages make this laccase-based electrode one of promising candidates as amperometric electrochemical sensor for application in sensing the specific phenol-like compound selectively.