O-Fenilendiamin ve Benzokinon Bazlı Polimer Filmle Oluşturulan Kolesterol Biyosensörünün Elektrokimyasal Karakterizasyonu

Aim: The detection of cholesterol concentration in the blood is an important parameter in the diagnosis and follow-up of many diseases, including cardiovascular and hepatobiliary diseases. Nowadays, various methods have been used for the routine analysis of cholesterol, including spectrophotometric, high-performance liquid chromatography (HPLC), and amperometric methods. Since biosensors have advantages such as high sensitivity, fast response, low cost, small size, continuous online detection, and reproducible results, it is aimed to develop a biosensor method for cholesterol determination. Methods: Polymer film immobilization was performed on the gold electrode surface electrochemically in an acetonitrile-water medium containing o-phenylenediamine and benzoquinone. Cholesterol oxidase (ChOx, E.C. 1.1.3.6) enzyme was immobilized on the polymer film-immobilized electrode surface by the self-forming monolayer method. Optimization and characterization studies were carried out for the determination of cholesterol with the prepared electrodes. Results: The determination of cholesterol was performed via monitoring the oxidation current of enzymatically produced H2O2 at 0.70 V Ag/AgCl. Optimum biosensor conditions were determined for phosphate buffer at 0.1M, pH 7.0, and 30°C for the Au/oPD-BQ/ChOx enzyme electrode. The linear working range is 9.8×10-6-1.1×10-2 mM, and the cholesterol detection limit is 9.8×10-6 mM. The analysis of total cholesterol in solutions was performed using the proposed Au/oPD-BQ/ChOx electrode. Conclusion: A convenient, simple, reproducible, and stable method was developed for the determination of cholesterol by immobilizing cholesterol oxidase on the prepared electrode surface through a polymer film. The sensor we designed can be expanded to improve the detection of many analytes in the clinic.