Enzymes are highly efficient and specific biocatalysts produced by the living cells in organisms, and they play very important roles in most life activities. The biosensors taking the enzyme as its molecular recognition component is endowed with many advantages such as high selectivity and high sensitivity. Since the introduction of the first biosensor by Clark and Lyons in 1962 and with the rapid development of biology, chemistry, physics, medicine, and electronic technology over the years, enzyme-based bi...