Bottlebrush Polymer Templates for the Synthesis of Gold Nanostructures and their Applications as Photothermal Agents and SERS Substrates

An innovative approach is presented for the synthesis of gold photothermal agents tailored for Near Infrared light NIR-I and NIR-II photothermal applications using bottlebrush polymers (BB) as soft templates (BB@Au). Upon exposure to NIR-I, (λ_ex = 808 nm) and NIR-II (λ_ex = 1064 nm) light, the photothermal agents (BB@Au) exhibit robust photothermal effects, achieving temperatures up to 58.3 °C under 500 mW cm^-2 NIR-II laser irradiation. This remarkable thermal response enables efficient eradication of cancer cells in both 2D and 3D settings. Furthermore, comprehensive studies demonstrate the biocompatibility of BB@Au, as evidenced by concentration-dependent and time-dependent analyses. Studies conducted with zebrafish larvae further confirm their safety, showing no abnormalities in hatching, survival, and histology sections. Aside from their enhanced photothermal effects, the BB@Au significantly enhances the Raman signal of adsorbed analytes. This allows their quantification and broadens the potential applications of the BB@Au particles as substrates for small molecules biosensing. The bottlebrush-based approach to produce novel gold nanostructures with augmented photothermal capabilities introduces a versatile strategy for developing precise and effective photothermal agents in a one pot process.