Nanocavity-enhanced plasmonic thermocycler for ultrafast polymerase chain reaction

Abstract

High-speed molecular diagnostics has attracted worldwide attention for rapid and accurate detection of diseases, preventing spread of infectious diseases and protecting public health. In particular, photothermal polymerase chain reaction (PCR) reduces the amplification procedure time by using the plasmonic photothermal (PPT) effect of specific nanomaterials, which generate localized heat. For example, various metallic nanomaterials are utilized to accelerate the PCR reactions such as Au nanoparticles, Au nanofilm, and Au nanoislands (AuNIs). However, the nanomaterial-based photothermal PCR still remains several problems, such as high nanoparticle concentrations and low optical absorption, causing the limited PCR efficiency. Here, we report a nanocavity-enhanced plasmonic thermal cycler for ultrafast thermocycling, which is composed of multilayer structures including ultrathin nanoislands film, dielectric layer and metallic film. Mirror on plasmonic nanoislands enables effective light trapping and generate interferences between the nanostructures, enhancing light absorption over the whole visible spectrum. The novel substrate allows enhanced light absorption and improved thermal control, resulting in highly efficient light-to-heat conversion from white light emitting diode (WLED) and providing great potential for a variety of applications in point-of-care molecular diagnostic technology.