Supersensitive nanothermometer based on CdSe/CdSxSe1-x magic-sized quantum dots with in vivo low toxicity

We report on the temperature dependence of the photoluminescence spectrum of CdSe/CdSxSe1-x magic -sized quantum dots (MSQDs), as well as the CdSe/CdSxSe1-x MSQDs biocompatibility in Drosophila mel-anogaster. We found that the emission intensity of CdSe/CdSxSe1-x MSQDs decreases while the full width at half-maximum (FWHM) increases with the temperature in the range of 306-343 K, under excitation at 376 nm. Combining these two characteristics, an optical nanothermometer was developed with a max-imum relative thermal sensitivity (Sr) of 6.9 %K-1 at 306 K, based on the ratio between the FWHM and the maximum emission intensity, which is one of the highest values of Sr reported in the literature related to ratiometric optical thermometry systems. Additionally, our results suggest that lower concentrations of CdSe/CdSxSe1-x MSQDs are biocompatible in model of Drosophila melanogaster. Taken together, our data suggested a translational potential for fluorescence and thermal images in nanomedicine with low toxicity.(c) 2022 Elsevier Ltd. All rights reserved.