LAUSR

Intracellular thermometry with favorable biocompatibility and precision is essential for insight into the temperature-related cellular events. Here, liquid-core nanocapsules as ratiometric fluorescent thermometers (LCN-RFTs) are prepared by encapsulating thermosensitive organic fluorophores (N, N'-di(2-ethylhexyl)-3,4,9,10-perylene tetracarboxylic diimide, DEH-PDI) with hydrophobic solvent (2,2,4-trimethylpentane, TMP) into the polystyrene/silica hybrid nanoshells. As the fluorescent thermosensitive unit of the LCN-RFT, the TMP solution of DEH-PDI bears the fluorescence response to temperature. Benefitting from the hydrophilic nanoshells, the LCN-RFTs exhibited favorable anti-interference and biocompatibility. Furthermore, the LCN-RFTs showed an excellent precision of 0.02-0.10 °C in a simulated physiological environment from 10.00 to 90.00 °C and were employed to realize intracellular thermometry with an outstanding precision of 0.06-0.14 °C. This work provides a feasible method of using hydrophobic organic fluorophores for intracellular thermometry by encapsulating them into the nanocapsules.