基于拮抗作用检测除草剂的类囊体膜生物传感器研究

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

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-Sb Q)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× 1 0 -3mol/ L Na Cl,5× 1 0 -3mol/ L Mg Cl2 和 0 .0 1 mol/ L H2 O2 的Tris-HCl缓冲溶液 (p H=7.4 )中 ,基于测量 0 .65 V处 H2 O2 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× 1 0 -9～ 1 .5× 1 0 -7mol/ L,敌草龙 1× 1 0 -8～ 3× 1 0 -7mol/ L,扑草净 4× 1 0 -8～ 3× 1 0 -6mol/ L,阿特拉津 1× 1 0 -7～ 5× 1 0 -6 mol/ L,莠灭净 1× 1 0 -7～ 5× 1 0 -6 mol/ L.利用 PVA-Sb Q光聚合膜固定类囊体 。

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 MgCl_2 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.