Institute of Cytology, Russian Academy of Sciences,194064 Saint Petersburg, Russia.
Higher School of Biomedical Systems and Technologies, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia.
Int J Mol Sci. 2023 Jan 31;24(3):2699. doi: 10.3390/ijms24032699.
Quantum dots (QDs) have attracted great attention as tools for theranostics that combine the possibility of simultaneous biological target visualization and medicine delivery. Here, we address whether core/shell InP/ZnS QDs (InP-QDs) may be an alternative to toxic Cd-based QDs. We analyze InP-QD photophysical characteristics in cell culture medium, salt solutions, and directly in the cells. It was demonstrated that InP-QDs were internalized into endolysosomes in HeLa and A549 cells with dynamics similar to Cd-based QDs of the same design, but the two cell lines accumulated them with different efficiencies. InP-QDs were reliably detected in the endosomes despite their low quantum yields. Cell culture medium efficiently decreased the InP-QD photoluminescence lifetime by 50%, acidic pH (4.0) had a moderate effect (20-25% reduction), and quenching by salt solutions typical of intra-endosomal medium composition resulted in a decrease of about 10-15%. The single-vesicle fluorescence-lifetime imaging microscopy analysis of QDs inside and outside the cells shows that the scatter between endosomes in the same cell can be significant, which indicates the complex impact of the abovementioned factors on the state of InP-QDs. The PI test and MTT test demonstrate that InP-QDs are toxic for both cell lines at concentrations higher than 20 nM. Possible reasons for InP-QD toxicity are discussed.
量子点 (QDs) 作为治疗诊断一体化工具引起了广泛关注，因为它可以将同时进行生物靶标可视化和药物传递的可能性结合起来。在这里，我们探讨了核壳型 InP/ZnS QDs（InP-QDs）是否可以替代毒性较大的基于 Cd 的 QDs。我们分析了 InP-QD 在细胞培养基、盐溶液中和直接在细胞中的光物理特性。结果表明，InP-QDs 以与同设计的基于 Cd 的 QDs 相似的动力学被内吞到 HeLa 和 A549 细胞的内溶酶体中，但这两种细胞系以不同的效率积累它们。尽管 InP-QD 的量子产率较低，但仍能可靠地在内体中检测到。细胞培养基通过将 InP-QD 光致发光寿命减少 50%来有效地猝灭，酸性 pH 值 (4.0) 具有适度的影响（减少 20-25%），而内体中典型的盐溶液猝灭导致约 10-15%的减少。对细胞内外 QDs 的单囊泡荧光寿命成像显微镜分析表明，同一细胞内的内体之间的散射可能很大，这表明上述因素对 InP-QD 状态的复杂影响。PI 测试和 MTT 测试表明，InP-QD 在浓度高于 20 nM 时对两种细胞系都有毒性。讨论了 InP-QD 毒性的可能原因。
