IMPROVEMENT OF THE ANALYTICAL CHARACTERISTICS OF AN ENZYME ELECTRODE FOR FREE AND TOTAL CHOLESTEROL VIA LAPONITE CLAY ADDITIVES

The electropolymerization of a laponite nanoparticle-amphiphilic pyrro le derivative-enzyme mixture preadsorbed on the electrode surface prov ides simultaneously the immobilization of the enzyme and the laponite particles in the polypyrrolic matrix. These incorporated laponite nano particles greatly enhance the sensitivity and stability of a cholester ol oxidase-based biosensor. Compared to a similar biosensor without la ponite, the biosensor sensitivity increased from 5.1 to 13.2 mA M(-1) cm(-2). Furthermore, the presence of hydrophilic laponite additive in the polymeric matrix containing cholesterol oxidase and cholesterol es terase is essential for the successful determination of total choleste rol.