Design and Optimization of a Lactate Amperometric Biosensor based on Lactate Oxidase and Multi Walled-Carbon Nanotubes

Lactate concentration in physiological fluids is an indicator of the energy production under anaerobic conditions of the whole organism [1]. Normal value for lactate level in blood ranges from 0.5 – 2.5 mM. Blood lactate values exceeding 7-8 mM are sometimes associated with a fatal outcome. The lactate level in blood is elevated under number of conditions. It is a major indicator of ischemic conditions, e.g. under the category of tissue hypoxia, the individual causes include shock (hypovolemic, cardiogenic or endotoxic), respiratory failure (asphyxia) and severe congestive heart failure. Gauging blood lactate is also relevant for the results of exercise and athletic performance [2]. Several approaches were made to develop a number of improved methods for lactic acid determination, such ad optic techniques (HPLC, mass spectroscopy, ion exchange chromatography, etc.) and electrochemical techniques (potentiometric and voltammetric detections, FET-based sensors, etc.) [1]. The present study is focused on development of technologies for lactate detection based on amperometric measures employing lactate oxidase (LOD). The project’s aim is double: the development of biosensors which can be integrated in Petri dishes for monitoring cell cultures, on one hand, and which can be integrated in point-of-care devices for human monitoring in personalized therapies, on the other hand. In both the cases, analysis of more than one substrate at the same time will be considered. Nanotechnology may be used in the optimization of electrodes with carbon nanotubes (CNT). Previous studies showed that CNTs can highly improve the electrocatalytic activity in electrochemical devices for monitoring metabolites [3].