Preparation of molecular layer for biosensing surface onto the FET gate surface was performed based on the previous reports[14,18]. After the reaction and specific adsorption of prion proteins to thiamine-immobilized FET gate surface, the proteins adsorbed on the surface were immersed with 10 L EDC solution and 10 LNHS solution at the same time for 10 min at room temperature.0.1 mg/mL of EDC and 0.6 mg/mL of NHS were prepared in 10 mMPBS (pH 6.3), separately.