▎ 摘　　要

NOVELTY - Use of fully covalently bonded fully reduced graphene oxide field effect transistor for constructing biosensor, is claimed. The constructing method comprises (i) connecting fully covalently bonded all-reduced graphene oxide field effect transistor comprising a source electrode and a drain electrode as an FET, dropping 5-15 mu l crosslinking agent solution to the surface of FET of the fully covalently-reduced graphene oxide field effect transistor, incubating for 0.5-2 hours, and washing the surface of the FET using phosphate buffered saline solution, where the crosslinking agent in the crosslinking agent solution is glutaraldehyde, a polypeptide condensation reagent HATU or 1-pyrene butyrate imide, (ii) dropping 5-20 mu l concentration of 50-150 mu g mL-1 antibody to the surface of the FET and incubating at room temperature of 20-25 degrees C for 1-2 hours, (iii) rinsing the surface of the FET with phosphate buffered saline solution. USE - The fully covalently bonded fully reduced graphene oxide field effect transistor is useful for constructing biosensor (claimed). ADVANTAGE - The biosensor achieves the purpose of simultaneously detecting different kinds of cancer markers. DETAILED DESCRIPTION - Use of fully covalently bonded fully reduced graphene oxide field effect transistor for constructing biosensor, is claimed. The constructing method comprises (i) connecting fully covalently bonded all-reduced graphene oxide field effect transistor comprising a source electrode and a drain electrode as an FET, dropping 5-15 mu l crosslinking agent solution to the surface of FET of the fully covalently-reduced graphene oxide field effect transistor, incubating for 0.5-2 hours, and washing the surface of the FET using phosphate buffered saline solution, where the crosslinking agent in the crosslinking agent solution is glutaraldehyde, a polypeptide condensation reagent HATU or 1-pyrene butyrate imide, (ii) dropping 5-20 mu l concentration of 50-150 mu g mL-1 antibody to the surface of the FET and incubating at room temperature of 20-25 degrees C for 1-2 hours, (iii) rinsing the surface of the FET with phosphate buffered saline solution, adding 5-20 mu l blocking agent to the surface of the FET and reacting for 1-2 hours to avoid non-specific adsorption to the gate surface of the fully-reduced graphene oxide field effect transistor, (iv) rinsing the surface of the FET with phosphate buffered saline solution, testing the transfer curve of the FET after drying at room temperature of 20-25 degrees C for at least 2 seconds, and obtaining Dirac point value D1, (v) adding 40-60 mu l of the solution to be tested to the surface of the FET obtained in the step (iv), incubating at room temperature of 20-25 degrees C for 1-3 hours, rinsing the surface of the FET with phosphate buffered saline solution, drying at room temperature of 20-25 degrees C for at least 2 seconds, testing the transfer curve, and obtaining the Dirac point value D2, and (vi) calculating Delta D is D2-D1, and recording the resulting difference Dirac point voltage difference Delta D as the sensing output signal.