title: Amperometric monitoring of lactate accumulation in rabbit ischemic myocardium.
abstract: Fabrication and characterization of miniature, flexible, planar biosensors for monitoring l-lactate accumulation in an ischemic myocardium are described. Three configurations of Au-based electrodes were fabricated by a photolithographic technique on flexible polyimide Kapton((R)) foil. All sensors are based on an immobilized lactate oxidase with amperometric detection of the enzymatically produced hydrogen peroxide at a platinum-electroplated-gold base electrode polarized at 0.5 V versus Ag/AgCl. An inner electropolymeric layer is used to prevent electrode fouling and to reject the interference effects of easily oxidizable molecules. In addition, a diffusion controlling outer layer that greatly enhances the linear dynamic range of the sensor, is obtained by casting a polyurethane external film. The developed sensor was evaluated in vitro and proved to have high selectivity, good operational stability, good accuracy and precision (average recovery = 102.3 +/- 0.4% for control sera), fast response time (t(95) = 20 s) and high upper limit of the linear dynamic range (25-80 mM, with sensitivity of 1.7-0.4 nA mM(-1) respectively at PO(2) = 15 mmHg). Subsequently, the sensor was brought into direct contact with the surface of the rabbit papillary muscle and used for continuous quantitative monitoring of extracellular lactate accumulation during no-flow ischemia.
authors.affiliation: Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Marzouk
authors.forename: V V
authors.initials: VV
authors.lastname: Cosofret
authors.forename: R P
authors.initials: RP
authors.lastname: Buck
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: W E
authors.initials: WE
authors.lastname: Cascio
authors.forename: S S
authors.initials: SS
authors.lastname: Hassan