The rapid advance and growth of the point-of-care diagnosis industry has provided an impetus for the development of novel signal labels for highly sensitive bio-molecule detections. Colloidal quantum dots (QDs) exhibit superior brightness, facile surface functionalization and exceptional photostability, making them the preferred option for these biological applications. However, the significantly reduced fluorescence intensity and limited photochemical stability in complex biological environments have greatly hampered their further use. Herein, with an innovative alloying engineering strategy, the high-quality water-soluble CdSe/CdxZn1−xS QDs with near-unity PL quantum yield and monoexponential PL decay dynamics are obtained. Notably, for the first time, a record-breaking stability at the single QD level in water with nonblinking behavior persisting for an hour is achieved, which approaching those of state-of-the-art hydrophobic QDs. Furthermore, the nanocomposites formulated with these novel alloyed QDs demonstrate a remarkable PL QY of 96 % and provide an ultrasensitive detection for prostate specific antigen on lateral flow immunoassays. These findings presented here shed new light on the design of high-brightness water-soluble QDs in single-molecule level and QDs-based nanocomposites, significantly pushing ahead toward high-sensitivity biomedical detections and diagnosis.

中文翻译：

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合金几何结构策略可实现高质量的水溶性量子点，用于超灵敏荧光免疫测定


即时诊断行业的快速发展和增长为开发用于高灵敏度生物分子检测的新型信号标记提供了动力。胶体量子点 （QD） 具有卓越的亮度、简单的表面功能化和出色的光稳定性，使其成为这些生物应用的首选。然而，在复杂生物环境中荧光强度的显着降低和有限的光化学稳定性极大地阻碍了它们的进一步使用。在此，通过创新的合金化工程策略，获得了具有近乎统一的 PL 量子产率和单指数 PL 衰变动力学的高质量水溶性 CdSe/CdxZn1−xS QDs。值得注意的是，首次在水中实现了单个 QD 水平的破纪录稳定性，并且不闪烁行为持续一小时，接近最先进的疏水性 QD 的稳定性。此外，用这些新型合金 QD 配制的纳米复合材料表现出 96% 的显著 PL QY，并在侧向层析免疫测定中为前列腺特异性抗原提供超灵敏检测。本文提出的这些发现为单分子水平和基于 QD 的纳米复合材料中的高亮度水溶性 QD 的设计提供了新的思路，极大地推动了高灵敏度生物医学检测和诊断的发展。