Polydopamine-Based Nanomaterials and Their Use in Sensor Applications

Polydopamine (PDA), originally a biomimetic coating polymer with remarkable adhesive properties, has evolved into a versatile material with diverse roles in multifunctional sensor design. This review comprehensively addresses recent developments in the properties of PDA-based nanomaterials and their integration into sensor platforms, going beyond their well-known advantageous properties to enhance optical, electrical, and mechanical characteristics, thus delivering advanced sensor performance. To provide a foundational context, the development of PDA-based nanomaterials, which can be used in versatile applications such as selective imprinting matrices, signal enhancers, and stabilizing agents for metallic and carbon-based nanostructures, is explored. Sensor applications are overviewed through four main techniques: electrochemical sensing, where PDA modulates electron transfer and molecular recognition; photonic and plasmonic platforms that utilize its broadband absorption; stimulus-sensitive systems that leverage its intrinsic photothermal properties; and flexible hydrogel-based electronics. By reviewing the most recent literature, it is demonstrated that integrating PDA-based nanomaterials into various sensors improves critical analytical performance parameters, such as sensitivity, stability, robustness, and accuracy. Finally, it sheds light on the outlook for future work aimed at solving technical issues such as repeatability and durability in PDA-based sensors.