Presently there are no means to make nerves regenerate across a gap caused by an injury to the spinal cord or peripheral nerves that will lead to neurological recovery. The circuit board unit has a bottom surface electrically mounted on the top surface of the main board, a top surface with a plurality of grounding pads, and a plurality of notches corresponding to the grounding pads of the main board. In particular, the invention discloses a rapidly reprogrammable electronic time-temperature tag that may be easily customized with the thermal time-temperature stability profile of an arbitrary material, using electronic data transfer methods.