The study of Nafion/xanthine oxidase/Au colloid chemically modified biosensor and its application in the determination of hypoxanthine in myocardial cells in vivo

Abstract

A novel hypoxanthine (Hx) microsensor was constructed. In this work, Nafion xanthine oxidase (XOD) and Au colloid were immobilized onto the surface of a Pt microelectrode. The enzyme biosensor displayed a quick and sensitive response to Hx. Under physiological conditions, a low detection limit, with high selectivity and sensitivity for Hx determination were obtained. The oxidation current [investigated using current–time (I–t) plots] was linear with Hx concentration ranging from 2.0 × 10⁻⁷ to 2.0 × 10⁻⁵ mol L⁻¹ with a calculated detection limit of 1.0 × 10⁻⁷ mol L⁻¹ (S/N of 3). The biosensor should be promising for in vivo measurement of Hx without interferences and fouling. The change of Hx concentration in cardiac myocytes stimulated by L-arginine (L-Arg) and acetylcholine (Ach) was also studied.