An electrostatic self-assembly route to prepare C-dots/gold nanoclusters for dual-emission ratiometric optical thermometry in living cells

It is of great significance to construct fluorescence-based nanothermometers via a convenient method. Herein, based on the opposite surface charges of carbon dots (CDs) and gold nanoclusters (Au NCs), a simple and facile self-assemble strategy was developed to obtain the CD/Au NC fluorescent hybrid nanomaterials via electrostatic interactions. At the excitation of 380 nm, the hybrid nanomaterials displayed a typical dual-emission behavior (455 nm and 600 nm). Because of the different thermal sensitivities of CDs and Au NCs, the dual-emission nanomaterials achieved the colorimetric detection of temperature in the range from 20 째C to 80 째C and showed high reproducibility. Furthermore, by taking advantage of the high stability and biocompatibility, the CD/Au NC fluorescent hybrid nanomaterials were further applied to achieve intracellular temperature detection. We expect that this dual-emission fluorescent nanothermometer will be a promising candidate for intracellular imaging and temperature sensing at the subcellular level.