Polymeric microneedles (MNs) based working electrodes are fabricated by standard photolithography of poly(ethylene glycol) diacrylate (PEGDA) doped by enzyme, redox mediator and photoinitiator. This flexible device acts as working electrode in electrochemical detection of glucose and lactic acid in solution when glucose oxidase (GOx) and lactose oxidase (LOx) enzymes, respectively, are used. Biosensor showed a linear response in the ranges from 0 to 4 mM and from 0 to 1 mM, for glucose and lactic acid, respectively. A limit of detection equal to 1 μM is found. The developed technology has been patented.