Reactivities of organic phase biosensors 3: Electrochemical study of cytochrome P450(cam) immobilized in a methyltriethoxysilane sol-gel

A composite amperometric biosensor was prepared by encapsulating a cytochro me P450(cam)/didodecyldimethylammonium bromide (DDAB) liquid crystal system in a methyltriethoxysilane (MTEOS) sol-gel (SG. The composite sensing laye r was cross-linked unto a 0.071 cm(2) glassy carbon electrode (GCE) using g lutaraldehyde. The electrochemical characteristics of the GCE-[P450(cam)/DA B/SG] biosensor were studied by multiscan cyclic voltammetry in aqueous pha se (0.05 phosphate buffer pH 7.3) and organic (CH3CN:H(2)0; 90%: 10%) phase anaerobic media. Analysis of the cyclic voltammetric results show that the sensor exhibited faster reversible electrochemistry in the organic phase t han in the aqueous phase. The cyclic voltammetric peak separation, Delta E- p, values estimated for the buffer and acetonitrile media were 62 mV and 10 4 mV, respectively. The sol-gel-based sensor had a life-time of 4 weeks whe n stored at 4 degrees C, and was stable up to 45 degrees C. which is also t he temperature of optimal sensor activity.