Abstract: A direct electron transfer amperometric biosensor fabricated using direct write printing technology for in vivo electrochemical monitoring, such as monitoring of neurotransmitters and other biomarkers, e.g., in traumatic spinal cord injury. The biosensor is fabricated by immobilizing glutamate oxidase on nanocomposite electrodes made of platinum nanoparticles, multiwall carbon nanotubes and a conductive polymer on a flexible substrate.