Novel Flexible Enzyme Laminate-Based Sensor for Analysis of Lactate in Sweat

Abstract We present work towards a novel amperometric enzyme-based highly flexible biosensor for real-time and non-invasive monitoring of lactate in human sweat for the early detection of pressure ischemia onset. The core of the recognition system is a highly flexible laminate, comprising two highly porous polycarbonate membranes, which provide support for the lactate oxidase enzyme (LOD), immobilised via covalent cross-linking. A number of variables were assessed to attempt to optimise the sensors, such as membrane pore size, crosslinking time, crosslinking agent concentration and levels of incorporated enzyme. Oxidation of lactate produces H 2 O 2 , which is subsequently determined electrochemically. The transducer comprises a two-electrode system on a single highly flexible polycarbonate membrane, sputter-coated with gold and platinum to render it conductive. The sensor exhibits lactate selectivity with a working range of 0–70 mM, thus covering physiologically relevant concentrations for pressure ischemia and has been shown to be suitable for determination of lactate in PBS, synthetic sweat and diluted human sweat.