An electro-enzymatic flexible molecular lactate sensor

We present the fabrication and electrochemical characterization of an electronic molecular lactate sensor comprised of an optimized three-electrode setup on a transparent, flexible polymer substrate. The sensors are functionalized with the flavoenzyme lactate oxidase as a selective, nanoscale recognition element. They exhibit an exceptionally high sensitivity in their linear range of ~ 370 μAmM^-1cm^-2, a very low detection limit of ~ 5 μM, and good thermal stability, with a working electrode area of only ~ 0.19 mm². We envision the sensors being utilized for one-time measurements of lactate levels in food or agricultural products for monitoring of their freshness, and show results of lactate level measurements for various dairy products.