The application discloses an
enzyme-
electron medium micro-nano composite for biosensing and a preparation method and application thereof. A
dehydrogenase for
electrochemical detection and an
electron medium are jointly loaded in a cavity of a carrier, the carrier is contracted through chemical or
physical stimulation, and
electron medium molecules in the cavity are forced to be distributed around active centers of the
dehydrogenase, so that a contractible limited
microsphere structure is obtained. The
enzyme-electron medium micro-nano composite obtained by the application can significantly improve a response current generated by unit
enzyme catalysis, enhance the stability of the enzyme, and effectively prolong the service life of a sensor.