Programmable DNA/Polyacrylamide Network‐Grafted Broadband Plasmonic Liquid Metal Nanoparticles for Ultrafast Real‐Time Molecular Diagnostics

Gallium-based room-temperature liquid metals (LMs) combine the desirable properties of metals and liquids, and possess highly reactive surfaces, emerging as a promising component in constructing smart soft composites for various applications, particularly in biosensing and diagnostics. Herein, we report on the development of an ultrafast, real-time molecular diagnostic platform based on gallium-based LM nanoparticles (LM NPs) grafted with programmable DNA/polyacrylamide networks. LM NPs with strong and broadband plasmonic light absorption are demonstrated as efficient photothermal agents to enable stable temperature cycles, and the LM surface-initiated polymerization reaction allows direct grafting of DNA/polyacrylamide copolymer networks onto LM NPs, yielding core-shell nanocomposites with significantly enhanced photothermal stability and capable of participating in enzymatic amplification reactions. Thanks to the efficient cascading of the photothermal process and the PCR-based amplification process, real-time detection of nucleic acid targets within 6.5 min is achieved, and the testing of different viral and bacterial targets with high sensitivity and specificity is achieved. The broadband light absorption of LM NPs also allows the molecular diagnostic platform works under portable LED devices, such as a LED flashlight, which can be further developed into low-cost, rapid POCT molecular diagnostic devices for practical disease diagnosis and other applications.