The soft peripheral nervous system is a desirable organ system for soft and conductive polymer-based electronic devices32 (link),33 (link). All procedures involving implantation and collecting of electrodes on rat sciatic nerves were performed in accordance with protocols approved by the Institutional Animal Care and Use Committee at Stanford University. Surgical procedures were described by a previously published protocol34 (link) with some modifications. Male Sprague Dawley rats (50–150g, Charles River) were given buprenorphine 0.1 mg per kg body weight intramuscularly before anesthesia and then anesthetized with 2% isoflurane in balanced oxygen. Under sterile conditions with external body warming, a 3-cm incision was made on the left thigh. About 1 cm of the sciatic nerve proximal to the tibial and peroneal bifurcation was either (1) inserted into the nerve cuff electrode (NS-NC-0.5–2-100PT-3–3-00–300-00, World Precision Instruments) or (2) wrapped with the MorphE. Muscle layers were closed with 4–0 silk sutures (Ethicon) and the skin was secured with Michel clips. At the end of week 4 or week 8 after surgery, rats were killed with carbon dioxide gas followed by decapitation for proper disposal. Sciatic nerves were collected for analysis.