title: Self-encapsulation of oxidases as a basic approach to tune the upper detection limit of amperometric biosensors.
abstract: This study describes a new, basic procedure for the tuning of some analytical parameters of enzymatic biosensors that are based on hydrogen peroxide-producing oxido-reductases. An amperometric biosensor based on glucose oxidase (GOx) (EC 1.1.3.4) from Penicillum vitale, immobilized on a carbon rod electrode by cross-linking with glutaraldehyde, was exploited as a model system for demonstration of the approach described here. Such an important analytical parameter as the upper detection limit was dramatically changed by the formation of a polypyrrole conducting polymer layer by the GOx-induced polymerization of polypyrrole (Ppy). An increase in the upper detection limits for differently modified electrodes was estimated by calculation of the apparent Michaelis-Menten constant [K(M(app))]. A significant increase in the long-term stability of the GOx-based electrode modified by Ppy (GOx/Ppy) was detected compared with that of an unmodified one. Further application of this approach, based on the self-encapsulation of glucose oxidase and other oxidases, is predicted for such biosensors where extension of the detection rate as well as K(M(app)) are required.
authors.affiliation: Center of Nanotechnology and Material Science, Faculty of Chemistry, Vilnius University, Naugarduko 24, 03225 Vilnius, Lithuania.
authors.forename: Arunas
authors.initials: A
authors.lastname: Ramanavicius
authors.forename: Asta
authors.initials: A
authors.lastname: Kausaite
authors.forename: Almira
authors.initials: A
authors.lastname: Ramanaviciene
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002384:Catalysis; D004563:Electrochemistry / Q000379:methods; D004800:Enzymes, Immobilized; D005949:Glucose Oxidase; D012680:Sensitivity and Specificity
chemical_list: D004800:Enzymes, Immobilized; D005949:Glucose Oxidase