Biosensor

A biosensor, comprising:

• a substrate;
• a working electrode disposed on the substrate, the working electrode comprising:
• a sensing electrode disposed on a top surface of the substrate;
• an enzyme reaction layer disposed on a top surface of the sensing electrode;
• and
• a permeation control layer disposed on a top surface of the enzyme reaction layer, the permeation control layer comprising a water-soluble polymer and a water-insoluble polymer;
• and
• a reference electrode disposed on the substrate to be spaced apart from the working electrode, so that the permeation control layer is spaced apart from the reference electrode,
• wherein the permeation control layer has a multi-layered structure from a double-layered structure to a penta-layered structure,
• wherein the permeation control layer is formed from a composition comprising a solvent including water, and a mixture of the water-soluble polymer and the water-insoluble polymer,
• the water-soluble polymer is included in an amount from 1 wt % to 10 wt % based on a total weight of the composition, and
• the water-insoluble polymer is included in an amount from 0.5 wt % to 5 wt % based on a total weight of the composition.