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 °C to 80 °C 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.