Abstract: The present invention forms a detection layer in an embedded biosensor probe by using a phenazine derivative as a redox mediator in which a phenazine group is covalently bonded to a high molecular weight polymer having a carboxyl group or an amino group, such as polyamino acid, polyimine, or polyallylamine; and the distance between the phenazine group and the high molecular weight polymer main chain is increased by using a polyethylene glycol chain.

Abstract: An amplifier circuit includes an operational amplifier to amplify an input signal input to a non-inverting input terminal, first and second feedback units to feed back an output signal output from the operational amplifier to an inverting input terminal of the operational amplifier, and a coupling unit to AC couple the second feedback unit and the inverting input terminal. The first feedback unit is to, together with the coupling unit, as a frequency of the output signal of the operational amplifier is increased, reduce an electric potential to be applied to the inverting input terminal with respect to the output signal. At the same time, the second feedback unit is to generate a predetermined electric potential lower than an electric potential of the output signal, the second feedback unit being configured to apply a predetermined electric potential to the inverting input terminal via the coupling unit.