Polymerization-Assisted Signal Enhancement and Visual Readout Techniques in Bioassays: A Mini Review

Polymerization-based strategies have emerged as powerful tools for enhancing sensitivity and enabling user-friendly visual outputs in bioassays. Unlike conventional assays that rely on catalyst- or enzyme-mediated accumulation of molecular products for signal amplification, polymerization reactions produce material-level, macroscopic, or supramolecular structures─such as hydrogels, polymer films, or insoluble precipitates. This mini review highlights recent advances in polymerization-assisted signal amplification techniques, with a particular focus on detection strategies and polymerization chemistries. We first classify detection approaches according to their readout mechanisms, including direct visual detection and integration with electronic or optical transducers. We then examine representative polymerization reactions employed in bioassays, including enzyme-mediated hydrogelation, nucleic acid polymerization, conductive polymer formation, and controlled radical polymerization. Both enzyme-dependent and enzyme-free systems are discussed, reflecting the growing versatility of polymerization-based platforms for biosensor development.