Electrochemical Synthesis of Conductive Melanin-Like Polymers for Non-Enzymatic Glucose Biosensors

Conductive polymers have been utilized in a wide range of biomedical applications due to their unique features such as electronic-ionic hybrid conductivity, mechanical softness, and easy modification. However, the trade-off between biocompatibility and electrochemical properties remains a challenge. Partial or complete replacement of the commonly used synthetic conductive polymers with the naturally-derived conjugated polymers such as melanin and their composites may be an alternative solution to overcome the current challenges. Melanin is a natural biopolymer with a conjugated backbone that supposedly provides conductive pathways. However, few studies have synthesized electrically device-level conducting melanin-like polymers (eMLPs) so far.<br/>In this study, eMLPs were electrochemically synthesized with tunable surface morphologies. All eMLP coated electrodes showed significantly lower electrochemical impedance spectra and superior charge storage capacities than a bare electrode. Also, in conjunction with its excellent conductivity, eMLP was demonstrated in glucose detection as a non-enzymatic biosensor with high sensitivity, a low limit of detection, and a wide linear range. This novel eMLP composite, with superior electrochemical performances, can be utilized in a wide range of bioelectronics applications, from <i>in situ</i> biosensors to implantable bionic interfaces.