Laccse Biosensor Based On Mesoporous Silica Sieves/PVA Composite Films As Immobilization Matrix

Laccase biosensor has capability of detecting a broad range of toxic substrates rapidly and conveniently in wastewater including phenolic compounds,arylamines,organic phosphonic compounds (pesticide),dioxins,and so on. So, it is valuable to fabricate laccse modified electrode with excellent properties such as high sensitivity, low detection limit, broad linear range and rapid response because of its important application in protecting environment.Three kinds of mesoporous silica sieves, MCM-41, MCM-41 containing Mg²⁺(denoted hereafter as Mg-MCM-41) and MCM-41 containing methylene Blue (denoted hereafter as MB-MCM-41), were synthesized by the methods of hydrothermal synthesis and were used to fabricate excellent laccase modified electrode firstly when poly(vinyl alcohol) (PVA) was in presence. N2 adsorption/desorption,SEM,TEM and electrochemical methods were used to characterize these modified electrodes.The results of MCM-41/PVA immobilized laccase modified electrode (denoted hereafter as MCM-41/PVA/Lac) showed that one proton participated in the electron transfer process on MCM-41/PVA/Lac modified electrode surface in pH 4.80 PBS containing 0.05mM catechol. Under optimization of the experimental parameters, MCM-41/PVA/Lac exhibited excellent response properties to catechol and improved sensitivity, response rate, linear range, detection limit and so on. MCM-41/PVA/Lac has an attracting application in detecting and inspecting wastewater.The results of Mg-MCM-41/PVA immobilized laccase modified electrode (denoted hereafter as Mg-MCM-41/PVA/Lac) showed that Mg2+ promoted catalytic oxidation of laccase and improved electron transfer between laccase and electrode,moreover, Mg-MCM-41/PVA/Lac exhibited better affinity to catechol, higher sensitivity, faster response, broader linear range and lower detection limit than MCM-41/PVA/Lac. Mg-MCM-41 provided a novel support for laccase modified electrode.The results of MB-MCM-41/PVA immobilized laccase modified electrode (denoted hereafter as MB-MCM-41/PVA/Lac) indicated that MB promoted catalytic oxidation of laccase and kept effective electron transfer of laccase modified electrode, moreover, MB-MCM-41 improved response properties of MCM-41/PVA/Lac such as sensitivity, response time and detection limit and so on and provided another novel support for laccase modified electrode.