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HJS and DHJS, two near-infrared emissive and mitochondria-targeted therapy probes, have been designed. They exhibited photothermal & photodynamic cytotoxicity and aggregation-induced emission (AIE) characteristics. Interestingly, we could receive fluorescence immediately after adding the probes without washing in 1 min. They could quickly enter cancer cells and selectively localized to the mitochondria firstly. When the concentration of probes was low (<5 μM), they could respond sensitively to the mitochondrial membrane potential and would selectively enter the mitochondria with red fluorescence. However, when the concentration was high (≥5 μM), they would preferentially enter the mitochondria and have the property of dual-channel fluorescence imaging (red and near-infrared) even after 24 h. What’s more, they increased the intracellular reactive oxygen species (ROS) levels, decreased the mitochondrial membrane potentials, and then induced apoptosis, which were proved by confocal imaging and flow cytometry experiments. In addition, the results of photothermal experiment and cytotoxicity test showed that the probes had good photothermal and photodynamic toxicity to cancer cells. In vitro and in vivo experiments also proved the excellent near-infrared (NIR) imaging ability, good biocompatibility and certain inhibition of tumor growth ability of DHJS.

Copper indium selenide (CISe) quantum dots (QDs) are a class of extremely appealing candidates for various biological applications due to their composition- and size-dependent photoluminescence and low toxicity. However, the synthesis of high-quality water-soluble CISe QDs with controlled composition in the aqueous phase is still a great challenge, which limits their biological applications. Moreover, the effects of the copper content in CISe QDs on the fluorescence and the corresponding mechanism are still subject to debate. Herein, a composition-tunable aqueous synthesis of high-quality Cu-deficient CISe QDs was presented, and the effects of the copper content on the fluorescence of CISe QDs was studied by the time-resolved fluorescence. The composition of CISe QDs could be flexibly controlled by manipulating the reaction temperature, the reaction time, and the Cu/In precursor ratio. The time-resolved fluorescence of CISe QDs with different Cu/In ratios suggested that the donor–acceptor pair (DAP) recombination was enhanced gradually with the increase of copper vacancies, resulting in the enhancement of fluorescence. However, if copper vacancies achieved an excessive concentration, the fluorescence would decrease possibly due to Auger recombination. The optimized CISe QDs with the maximum quantum yield of 10.3% were obtained with the Cu/In ratio, reaction temperature, and reaction time of 1/5, 170 °C, and 1 h, respectively. Based on the intense emission of the Cu-deficient CISe QDs, a highly sensitive “turn-on” fluorescent probe was developed for the detection of adenosine triphosphate (ATP) in living cells with a limit of detection of 56 nM. This work provides a paradigm for the aqueous-phase synthesis and applications of ternary I–III–VI QDs.

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With the emergency and rapid development of super-resolution fluorescence microscopy, monitoring mitochondrial morphological changes has arouse researcher’s great interest to explore the role of mitochondria in the process of cell...