Single-Step Fabrication of Resonant Silicon–Gold Hybrid Nanoparticles for Efficient Optical Heating and Nanothermometry in Cells

Heat is a well-known treatment method for a wide range of diseases. Hyperthermia treatment or intentional overheating of cells is a rapidly developing therapeutic strategy in cancer treatment. All-dielectric nanophotonics has established itself in optical applications, including nanothermometry and optical heating; generally, it involves Mie resonances in nonplasmonic nanoparticles (NPs). However, such nanomaterials do not always provide sufficient heating due to their nonoptimal size distribution after fabrication by nonlithographic approaches. To overcome this limitation, additional steps, such as size-separation of NPs, are required. Another strategy for efficient heating is intelligent integration of plasmonic and all-dielectric nanostructures to develop hybrid nanomaterials with outstanding optical performances, e.g., efficient nanoheaters and nanothermometers. Taking this into account, we report on a simple and accessible approach for the fabrication of hybrid silicon–gold NPs. Their heating abilities are further compared with those of pristine monodispersed Si NPs inside and outside B16–F10 melanoma cells and confirmed by simultaneous nanoscale thermometry. The obtained results show that the obtained hybrid nanomaterials are more efficient nanoheaters even in biological environments, where cell inhomogeneity and deviations of NP sizes make it difficult to exactly meet the critical coupling conditions.