Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and subcellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. The combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM. Detection of highly resolved long-lifetime (ms) PL decay curves from small (∼10 μm²) areas within single cells within a few seconds emphasized the unprecedented photophysical properties of Tb-NPs for live-cell imaging that extend well beyond currently available nanometric imaging agents.

中文翻译：

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使用Ter纳米颗粒的无自发荧光活细胞成像

荧光纳米颗粒（NPs）已成为高级细胞和亚细胞成像不可替代的工具。虽然非常亮的NP需要用紫外线或可见光激发，这会产生强大的生物成分自发荧光，但是没有自发荧光问题的可被NIR激发的NP却显示出低得多的亮度。在这里，我们展示了一种新型的表面光敏ter NP（Tb-NP）在活HeLa细胞中无自发荧光细胞内成像的应用。高亮度，高光稳定性和长光致发光（PL）寿命相结合，可有效抑制短时自发荧光，可在72小时内对细胞内囊泡进行门控PL成像，且无毒性且Tb-NP浓度极低低至12 pM。²）几秒钟内单个细胞内的区域强调了Tb-NP用于活细胞成像的空前的光物理特性，其范围远远超出了当前可用的纳米成像剂。