Development and application of estradiol sensor based on layer-by-layer assembling technique

Abstract

A simple strategy for the modification of disposable combination graphite-clay electrode, pencil graphite electrode (PGE), by multi-walled carbon nanotube- gold nanoparticle (MWNT-GNP) composite multilayers was proposed as a sensor to determine estradiol. The modification was carried out by the layer-by-layer (LBL) assembling of polyethyleneimine (PEI), decorated GNPs and polyacrylic acid (PAA) functionalised MWNTs via electrostatic interactions on a negatively charged PGE. The resulting MWNT-GNP multilayer modified PGE (MWNT-GNP/PGE) exhibited a sensitive electrochemical response towards the oxidation of estradiol at 0.90 V. Under optimal working conditions, the oxidation current of estradiol at MWNT-GNP/PGE increased linearly with its concentration in the range 7.0×10-8-4.2×10-5 mol l-1, with a low-detection limit of 1.0×10-8 mol l-1 for 200 s accumulation at an open circuit. This sensor was successfully applied to the detection of estradiol in blood serums. © 2011 Taylor & Francis.