Abstract: Provided is a glycated protein sensor provided with: immobilized protease; immobilized ketoamine oxidase; and a hydrogen peroxide detection section.

Abstract: Provided is an electrical circuit for electrochemical measurement of a solution, said electrical circuit comprising: a voltage generation circuit; an operational amplifier that has an output (OUT), a non-inverting input (+IN), and an inverting input (?IN), wherein the output (OUT) is connected to a counter electrode (CE) in contact with the solution, the inverting input (?IN) is connected to a reference electrode (RE) in contact with the solution, and the non-inverting input (+IN) is connected to the voltage generation circuit; a capacitor that is connected between the output (OUT) and inverting input (?IN) and has a capacitance of 1 ?F or greater; and a current measurement circuit that is connected to a working electrode (WE) in contact with the solution.

Abstract: [Problem to be Solved] A biosensor having high detection sensitivity and detection specificity is provided. [Solution] There is provided a biosensor comprising: an identification substance capable of binding to a substance to be detected; and an electrode charged with a charge of the identification substance, and detecting a change in a charge density of the electrode caused by binding of the substance to be detected to the identification substance, wherein a polymer layer in which a molecular template having a structure complementary to a molecular structure of the substance to be detected is formed is formed on all or part of a surface of the electrode, the identification substance is contained in the polymer layer, and the polymer layer is an ultrathin film layer.