Biosensors are analytical devices that can detect the presence or concentration of a chemical substance by combining a biological component with a physicochemical detector . The biological component can be any biomolecule or organism that has a specific affinity or recognition for the target substance, such as an enzyme, an antibody, a nucleic acid, a cell, a tissue, or a microorganism . The physicochemical detector can be any transducer that can convert the bio-recognition event into a measurable signal, such as an optical, electrochemical, piezoelectric, or thermal signal . Biosensors have many advantages over conventional analytical methods, such as simplicity, speed, low cost, high sensitivity, and selectivity.Nanomaterials are considered promising candidates for biosensor development .