Preparation of amperometric glycated hemoglobin biosensor based on zinc oxide nanoparticles fructosyl amino acid oxidase conjugate

Abstract

Measurement of HbA1c level in blood provides long-term glucose level in diabetic patients without influence of short-term fluctuations. The existing methods for HbA1C determination including biosensors suffer from insufficient sensitivity, detection limit, response time and storage stability. These problems were overcome in the present biosensor. A method is described for construction of an amperometric glycated hemoglobin (HbA1C) biosensor by immobilizing a fructosyl amino acid oxidase (FAO) onto ZnONPs/PPy hybrid film deposited on Au electrode and using it as working electrode, Ag/AgCl as reference electrode and Pt as auxillary electrode. The whole blood samples were hemolyzed and digested by protease before measuring their HbA1C level by the biosensor. The enzyme electrode detected FV as low as 50 and#61549;M at a signal to noise ratio of 3 within 2 s at +0.27 V vs. Ag/AgCl, pH 7.0 and 35oC with a linear working range, 0.1 to 3.0 mM for fructosyl valine (FV) and sensitivity of 38.42 and#61549;A mM-1. The electrode showed only 30% loss of its initial response over a period of 160 days, when stored at 4oC. Biosensor measured HbA1C in whole blood of apparently healthy and diabetic patients and found to be in the range, 4.0-5.6% and 5.7-12.0% respectively. The use of FAO/ZnONPs/PPy/Au electrode resulted into improved amperometric glycated hemoglobin biosensor.