Novel potentiometric cholesterol sensor for the quantitative estimation of total cholesterol in human blood serum

A process for the preparation of potentiometric biosensor for the quantitative estimation of total cholesterol in human blood serum and the said process comprises the steps of:

• a) preparing an ion exchange field effect transistor (ISFET) having an open dielectric SiO2—Si3N4 gate on p-type Czochralski silicon wafers by known method,
• b) reacting cholesterol chloroformate with 3-amminopropyl triethoxysilane in a weight ratio of 1.5:0.5 to 2.5:1.5 in dichloromethane, under stirring, in an ice bath, for a period of 5-10 hrs, followed by adding triethyl amine and further stirring for 10-14 h hrs to obtain the resultant product of the complex of cholesterol chloroformate (CCF) and 3-amminopropyl triethoxysilane (APTS),
• c) adding triethoxy silane drop wise to the above said resultant reaction product obtained in step (b) and subsequently adding ethanol and aqueous HCl having pH 2 in a ratio of 1.5:1 to 2.5:1.5 and stirring the reaction mixture for 5-7 days in an ice bath, followed by keeping it in an oil bath at a temperature of 40-45° C. for 22-26 hrs. and subsequently raising the temperature of the oil bath to 70-75° C. and heating the reaction mixture for 46-50 hrs, followed by the removal of product,
• d) washing the resultant product obtained in step (c) with acetone to remove the cholesterol template, followed by grounding to obtain the desired. molecular imprinted monolith in powder form,
• e) preparing a slurry of the molecular imprinted monolith powder in acetone,
• f) applying the slurry of molecular imprinted monolith obtained in step (e) on the open dielectric SiO2—Si3N4 gate of ion exchange field effect transistor (ISFET) of step (a), followed by the evaporation of acetone to obtain the desired working electrode cholesterol sensor.