A New Laccase Biosensor For Polyphenols Determination

Abstract

Abstract:The relevance of polyphenols in human health is a well known fact. Prompted by that, very intensive research has been directed to get a method to detect them, which will improve the current ones. Laccase (p-diphenol:dioxygen oxidoreductase, EC 1.10.3.2) is a multi-copper oxidase, which couples catalytic oxidation of phenolic substrates with four electron reduction of dioxygen to water [1] . A maximum catalytic response in oxygenated electrolyte was observed between 4.5 and 5.5 [2], while for pH > 6.9 the laccase was found to be inactive [3]. We prepared a biosensor with laccase immobilised on a polyether sulphone membrane, at pH 4.5, which was applied at Universal Sensors base electrode. Reduction of the product of oxidation of several polyphenols, catalysed by laccase, was done at a potential for which the polyphenol of interest was found to respond. Reduction of catechol was found to occur at a potential of -200mV, which is often referred to in the literature for polyphenolic biosensors. However other polyphenols did not respond at that potential. It was observed that (+)-catechin produced a very large cathodic current when +100mV were applied to the laccase biosensor, both in aqueous acetate and 12% ethanol acetate buffer , whereas caffeic acid responded at -50mV. Other polyphenols tested were gallic acid, malvidin, quercetin, rutin, trans-resveratrol.

Methods for Total Antioxidant Activity Determination: A Review

“…Several amperometric biosensors for the detection of phenolic compounds have been developed, on the basis of enzymes, such as tyrosinase, laccase or peroxidase [106][107][108][109]. Biosensors for phenolic compounds were constructed by immobilizing polyphenol oxidase (PPO) into conducting copolymers prepared by electropolymerization of pyrrole with thiophene capped polytetrahydrofuran [108].…”

Imobilização da lacase em micropartículas de quitosana obtidas por spray drying e usadas na construção de biossensores

“…[45][46][47][48] A Tabela 2 apresenta alguns parâmetros analí-ticos como linearidade, limite de detecção, estabilidade dos biossensores contendo lacase imobilizada descritos na literatura e os encontrados no presente trabalho empregando os biossensores (I) e (II). Como se pode observar, as figuras de mérito obtidas com os biossensores desenvolvidos são semelhantes às reportados na literatura, ressaltando-se que um maior tempo de vida é apresentado pelos biossensores propostos.…”

Laccase Biosensor Based on N‐Succinimidyl‐3‐Thiopropionate‐Functionalized Gold Electrodes

“…In this context, electrochemical biosensors with laccase as biological recognition element for the analysis of phenols have been developed by its immobilization on different electrode surfaces such as carbon fibers [12], glassy carbon [13,14], graphite [15 -18], carbon paste [19], polyethersulfone membranes on an Universal Sensors base electrode [20], polyaniline-modified interdigitated Pt sensors [21], PVP -gel deposited on a Clark electrode [22], and gold surface [23].…”