▎ 摘　　要

NOVELTY - Preparing cobalt-nitrogen co-doped carbon nano-tube modified graphene fiber comprises (i) injecting graphene oxide solution into coagulation bath by wet spinning method, where graphene oxide is gelled and separated out to obtain graphene oxide fiber, (ii) reducing graphene oxide fiber to obtain graphene fiber, placing in mixed solution of dimethyl imidazole and cobalt salt to obtain zeolitic imidazolate framework-67 (ZIF-67) modified graphene fiber, and (iii) placing ZIF-67 modified graphene fiber in a tubular furnace to calcine under inert atmosphere, placing melamine, urea, ZIF-67 or dicyandiamide at the front end of ZIF-67 modified graphene fiber, and making melamine, urea, ZIF-67 or dicyandiamide be nitrided and carbonized, using tip growth mechanism of carbon nano tube, using ZIF-67 modified graphene fiber dispersed in cobalt ion as catalyst and growing cobalt-nitrogen co-doped carbon nano-tube on graphene fiber surface. USE - The fiber is useful as nano-enzyme electrochemical biosensor for detecting concentration of hydrogen sulfide in colorectal cancer cell (claimed). ADVANTAGE - The fiber material detects the concentration of hydrogen sulfide in colorectal cancer cell, or simulates peroxidase and catalase to consume active oxygen in the cell to protect the cell.