Polydopamine-mediated gold nanoparticle coating strategy and its application in photothermal polymerase chain reaction

Materials with high light-to-heat conversion efficiencies offer valuable strategies for remote heating. These materials find wide applications in photothermal therapy, water distillation, and gene delivery. In this study, we investigated a universal coating method to impart photothermal features to various surfaces. Polydopamine, a well-known adhesive material inspired by mussels, served as an intermediate layer to anchor polyethyleneimine and capture gold nanoparticles. Subsequently, the coated surface underwent electroless gold deposition to improve photothermal heating efficiency by increasing light absorption. This process was analyzed through scanning electron microscopic imaging and absorbance measurements. To demonstrate functionality, the coated surface was photothermally heated using a light-emitting diode controlled with a microprocessor, targeting the metal regulatory transcription factor 1 gene-a marker for osteoarthritis-and the S gene of the severe fever with thrombocytopenia syndrome virus. Successful amplification of the target genes was confirmed after 34 polymerase chain reaction cycles in just 12 min, verified by gel electrophoresis, demonstrating its diagnostic applicability. Overall, this simple photothermal coating method provides versatile utility, and is applicable to diverse surfaces such as membranes, tissue culture dishes, and microfluidic systems.