Gold-Nanoparticle Decorated Graphene-Nanostructured Polyaniline Nanocomposite-Based Bienzymatic Platform for Cholesterol Sensing

Deepshikha Saini,T. Basu,Ruchika Chauhan,Pratima R. Solanki

doi:10.5402/2012/102543

Abstract

A novel nanobiocomposite bienzymatic amperometric cholesterol biosensor, coupled with cholesterol oxidase (ChOx) and horseradish peroxidase (HRP), was developed based on the gold-nanoparticle decorated graphene-nanostructured polyaniline nanocomposite (NSPANI-AuNP-GR) film which was electrochemically deposited onto indium-tin-oxide (ITO) electrode from the nanocomposite (NSPANI-AuNP-GR) dispersion, as synthesized by in situ polymerization technique. The gold nanoparticle-decorated graphene-nanostructured polyaniline nanocomposite (NSPANI-AuNP-GR) offers an efficient electron transfer between underlining electrode and enzyme active center. The bienzymatic nanocomposite bioelectrodes ChOx-HRP/NSPANI-AuNP-GR/ITO have exhibited higher sensitivity, linearity, and lowerKmvalue than monoenzymatic bioelectrode (ChOx/NSPANI-AuNP-GR/ITO). It is inferred that bienzyme-based nanobioelectrodes offer wider linearity (35 to 500 mg/dL), higher sensitivity (0.42 μAmM−1), low km value of 0.01 mM and higher accuracy for testing of blood serum samples than monoenzyme system. Mechanism of the overall biochemical reaction has been proposed to illustrate the enhanced biosensing performance of the bienzyme system. The novelty of the electrode lies on reusability, extended shelf life, and accuracy of testing blood serum samples.

Highlights

Graphene, one of the most exciting nanostructures of carbon, is a two-dimensional honeycomb crystalline single layer of carbon lattice [1,2,3]
In the FT-IR spectrum of Cholesterol oxidase (ChOx)/nanostructured polyaniline (NSPANI)-AuNP-graphene nanosheet (GR)/ITO and ChOx-horseradish peroxidase (HRP)/NSPANIAuNP-GR bioelectrode (Figures 2(b) and 2(c)), enzyme binding is indicated by the appearance of additional absorption bands at 1524 and 1630 cm−1 assigned to the carbonyl stretch and N–H bending, respectively [45]
Gold-nanoparticle-decorated graphene-nanostructured polyaniline nanobioelectrodes have been fabricated from the NSPANI-AuNP-GR nanodispersion as synthesized via in situ polymerization, using electrodeposition technique, for the development of reusable cholesterol biosensor

Summary

Introduction

One of the most exciting nanostructures of carbon, is a two-dimensional honeycomb crystalline single layer of carbon lattice [1,2,3]. Gold nanoparticles (AuNP) have many unique properties such as high surface free energy, strong adsorption ability, well suitability, and good conductivity [23, 24] It can provide more binding sites and more congenial microenvironment for biomolecules immobilization to retain the bioactivity of the proteins, which can prolong the life time of biosensor [25, 26]. Some improved biosensors based on the coupled enzyme reactions have been reported to detect hydrogen peroxide at low potential [37, 38]. The novelty of the sensor lies on the method of fabrication of transducer matrix coupled with enzyme system, reusability, reliability, extended shelf life, sensitivity, and successful application to blood serum testing

Experimental

Synthesis of Gold-Nanoparticle-Decorated

Findings

Discussion

Conclusion