Sensitive Biomimetic Sensor Based on Molecular Imprinting at Functionalized Indium Tin Oxide Electrodes

We initially report an electrochemical sensing platform based on molecularly imprinted polymers (MIPs) at functionalized Indium Tin Oxide Electrodes (ITO). In this research, aminopropyl-derivatized organosilane aminopropyltriethoxysilane (APTES), which plays the role of functional monomers for template recognition, was firstly self-assembled on an ITO electrode and then dopamine-imprinted sol was spin-coated on the modified surface. APTES which can interact with template dopamine (DA) through hydrogen bonds brought more binding sites located closely to the surface of the ITO electrode, thus made the prepared sensor more sensitive for DA detection. Potential scanning is presented to extract DA from the modified film, thus DA can rapidly and completely leach out. The affinity and selectivity of the resulting biomimetic sensor were characterized using cyclic voltammetry (CV). It exhibited an increased affinity for DA over that of structurally related molecules, the anodic current for DA oxidation depended on the concentration of DA in the linear range from 2×10⁻⁶ M to 0.8×10⁻³ M with a correlation coefficient of 0.9927. In contrast, DA-templated film prepared under identical conditions on a bare ITO showed obviously lower response toward dopamine in solution. It should be noted that potential scanning is a very effective approach for DA extraction, and surface modification of the electrochemical transducer with functional monomers is responsible for the development of MIPs-based highly sensitive biomimetic sensor.