Review—Recent Advances in Polydopamine-based Electrochemical Biosensors

The biosensor is a rapidly expanding field of science owing to its wide variety of applications in healthcare, pharmacology, environmental control, food quality assessment, security and defense, and, most notably, diagnostics. Among biosensors, electrochemical biosensors are immensely popular because of their high sensitivity, low detection limit, automation capabilities, low testing cost, and the emergence of electrochemical disposable devices capable of dealing with extremely small sample volumes. Biomolecule immobilization is a crucial step in biosensor development that necessitates the functionalization of the transducer surface. In 2007, polydopamine (PDA) is introduced as a substrate-independent coating material rich in catechol, imine, and amine groups, which provides a perfect environment for dense biomolecule immobilization on the transducer surface. PDA brings the world of possibilities for attaching biomolecules, changing their bio-catalytic capabilities, transferring electrons rapidly, and offering a rapid interface to provide a range of electrochemical signals to design unique diagnostic tools. This review attempts to assemble existing research progressed on PDA-based electrochemical biosensors in terms of enzymatic biosensors (based on H 2 O 2 , glucose, alcohol, and laccase), genosensors (DNA sensing), immunosensors, and aptasensors. Further, literature on the detection of thrombin, tumour markers, amino acids, and other therapeutically significant analytes has been collated to provide a comprehensive assessment of PDA-based biosensors. Furthermore, the future potential of PDA-based biosensors for the construction of smart sensor systems leveraging artificial intelligence and Internet of things technologies was discussed in this article.