Fabrication of Pt based amperometric cholesterol biosensor using cellulose acetate membrane

Abstract

Cholesterol esterase, cholesterol oxidase and horseradish peroxidase (HRP) have been co-immobilized onto cellulose acetate membrane, which is mounted over biosensor, Pt electrode. Biosensor showes excellent performance with a linear response between 2.5 to 50 mg dl⁻¹ of cholesterol acetate [correlation coefficient (r) = 0.9912]. Mean analytical recovery of added cholesteryl acetate (100 and 200 mg dl⁻¹) in serum (n=6.0) has been found to be 99.86±0.78 and 97.79±0.73. Cholesterol content of sera within batch and between batch coefficient of variation (CV) are <3% and < 5 %, respectively. Km for cholesterol acetate and Vmax are 1083 mg/dl⁻¹ and 0.5 mA/sec. Optimum pH of biosensor is 7.0 and temperature 45°C. Enzyme electrode lost 50% of its activity during its regular use for 150 times over a period of 25 days at 4°C. The response time is 35 second. Uric acid and ascorbic acid shows slight interference.