▎ 摘　　要

NOVELTY - Method for absorbing bio material involves doping and returning a graphene oxide with nitrogen, obtaining buffer solution containing an alkaline earth metal and a biomaterial, absorbing the biomaterial by dripping the buffer solution on the graphene oxide dipped and returned with nitrogen. USE - Method for absorbing biomaterial used for manufacturing composite substrate for electronic circuit for flexible electrode (all claimed). ADVANTAGE - The biomaterial is efficiently absorbed with high selectivity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for manufacture of composite substrate.