基于拮抗作用检测除草剂的类囊体膜生物传感器研究

利用除草剂对植物类囊体束缚酶分解过氧化氢的拮抗作用,研制了一种快速检测痕量除草剂的电化学生物传感器.将植物类囊体用聚乙烯醇-苯乙烯吡啶(PVA-SbQ)光敏聚合剂在紫外光诱导下产生大分子网状结构进行包埋,制成生物敏感膜,并固定在铂电极表面.根据加入除草剂时类囊体膜束缚酶分解过氧化氢活性的变化,对除草剂进行测定.在含有1×10^-3mol/LNaCl,5×10^-3mol/LMgCl₂和0.01mol/LH₂O₂的Tris-HCl缓冲溶液(pH=7.4)中,基于测量0.65V处H₂O₂氧化电流的变化,可以对下列浓度的除草剂进行定量检测:百草枯3×10^-9～1.5×10^-7mol/L,敌草龙1×10^-8～3×10^-7mol/L,扑草净4×10^-8～3×10^-6mol/L,阿特拉津1×10^-7～5×10^-6mol/L,莠灭净1×10^-7～5×10^-6mol/L.利用PVA-SbQ光聚合膜固定类囊体,能够使酶的活性在低温下保持数月.

A Thylakoid Membrane Biosensor Based on the Antagonism of Thylakoid-bound Enzymes for Determining Herbicide

An electrochemical biosensor for determination of herbicide was prepared. It was based on the antagonism of herbicides on the decomposition of hydrogen peroxide catalyzed by the thykaloid-bound enzymes. The thylakoid membrane isolated from spinach leaves was immobilized by entrapment in polyvinylalcohol bearing styrylpyridinium groups(PVA-SbQ). The thylakoid membrane was fixed on the head of a platinum electrode. Oxidative current of hydrogen peroxide was detected by differential pulse voltammetry in Tris-HCl buffer solution(pH=7.4) containing 1×10-3 mol/L NaCl, 5×10-3 mol/L MgCl2 and 0.01 mol/L hydrogen peroxides. Some herbicides have been detected in the concentration ranges of 3×10-9-1.5×10-7 mol/L for paraquat, 1×10-8-3×10-7 mol/L for diuron, 4×10-8-3×10-6 mol/L for prometryn, 1×10-7- 5×10-6 mol/L for atrazine and 1×10-7- 5×10-6 mol/L for ametryn, respectively. The method for immobilizing thylakoid in PVA-SbQ membrane was found to be promising to make enzymes stable for several months. The mechanism for this antagonism on the enzymatic decomposition of hydrogen peroxide has been discussed.