Fabrication and Optimization of ChE/ChO/HRP-AuNPs/c-MWCNTs Based Silver Electrode for Determining Total Cholesterol in Serum.

Kusum Lata,Vikas Dhull,Vikas Hooda

doi:10.1155/2016/1545206

Abstract

The developed method used three enzymes comprised of cholesterol esterase, cholesterol oxidase, and peroxidase for fabrication of amperometric biosensor in order to determine total cholesterol in serum samples. Gold nanoparticles (AuNPs) and carboxylated multiwall carbon nanotubes (cMWCNTs) were used to design core of working electrode, having covalently immobilized ChO, ChE, and HRP. Polyacrylamide layer was finally coated on working electrode in order to prevent enzyme leaching. Chemically synthesised Au nanoparticles were subjected to transmission electron microscopy (TEM) for analysing the shape and size of the particles. Working electrode was subjected to FTIR and XRD. The combined action of AuNP and c-MWCNT showed enhancement in electrocatalytic activity at a very low potential of 0.27 V. The pH 7, temperature 40°C, and response time of 20 seconds, respectively, were observed. The biosensor shows a broad linear range from 0.5 mg/dL to 250 mg/dL (0.01 mM–5.83 mM) with minimum detection limit being 0.5 mg/dL (0.01 mM). The biosensor showed reusability of more than 45 times and was stable for 60 days. The biosensor was successfully tested for determining total cholesterol in serum samples amperometrically with no significant interference by serum components.

Highlights

With increasing mortality rate due to cardiovascular diseases (CVDs) in present scenario, it is necessary to develop more advanced methods for diagnosis
Cholesterol esterase was purified from Pseudomonas species (165.8 Units/g); 4-aminophenazone, Triton X-100, cholesteryl acetate, and carboxylated multiwalled carbon nanotubes (c-MWCNTs) were purchased from Sigma Chemical Co., USA
The lab synthesised AuNPs were characterized by transmission electron microscopic (TEM) study

Summary

Introduction

With increasing mortality rate due to cardiovascular diseases (CVDs) in present scenario, it is necessary to develop more advanced methods for diagnosis. These advanced diagnostic methods should sense the disease at an early stage and prevent it from being fatal. Cholesterol is considered as risk factor when the blood cholesterol is above the normal level and so causes the risk of cardiovascular disease (CVD) [1]. Elevated level of cholesterol in blood is one of the factors responsible for coronary artery disease, hypertension, nephritic syndrome or cirrhosis, atherosclerosis, heart attack, and stroke [2]. When too much of cholesterol circulates in the blood, it slowly builds up layer inside the inner walls of the arteries which makes them narrow and less flexible [2]

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Conclusion