Water‐soluble K₅HoLi₂F₁₀ (KHLF) nanoprobes with the excitation and emission both in the near‐infrared (NIR) region were developed and first demonstrated for in vivo imaging of living mice. The PEG₄₀₀ coating endows the nanoprobes with good water solubility and biocompatibility. Doping with Ho³⁺ ions is capable of emitting NIR fluorescence with two peaks centered, respectively, at 887 and 1,180 nm once excited by a 808 nm laser; meanwhile, it also possess good photothermal conversion performance. The KHLF matrix with specifically structure of large ion‐distance and low photon energy imparts the nanoprobes low quenching effect and excellent photostability (fluorescence decrease <5% upon 120 min illumination of 808 nm continuous laser with a power density of 1 W/cm²). The nanoparticles (NPs) were tested for in vitro bioimaging with living mice. The results show the NPs have low biotoxicity, rapid metabolism, normal biodistribution, together with the photothermal imaging performance and a high‐contrast fluorescence images (signal‐to‐background ratio of 14:1). The superior performances of these nanoprobes in vivo imaging of mice proclaim the great potential of this type of probe for high‐contrast imaging and photothermal treatment in practical applications.

中文翻译：

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一种用于体内成像的新型光稳定近红外到近红外荧光纳米颗粒。

在近红外 (NIR) 区域具有激发和发射的水溶性 K ₅ HoLi ₂ F ₁₀ (KHLF) 纳米探针被开发出来并首次被证明用于活体小鼠的体内成像。PEG ₄₀₀涂层赋予纳米探针良好的水溶性和生物相容性。兴奋剂何³⁺一旦被 808 nm 激光激发，离子能够发射具有两个中心峰的 NIR 荧光，分别位于 887 和 1,180 nm；同时，它还具有良好的光热转换性能。具有大离子距离和低光子能量的特殊结构的 KHLF 基质赋予纳米探针低猝灭效应和优异的光稳定性（在功率密度为 1 W/cm ²的 808 nm 连续激光照射 120 分钟后，荧光降低 <5%）。纳米颗粒 (NPs) 在活体小鼠身上进行了体外生物成像测试。结果表明，纳米颗粒具有低生物毒性、快速代谢、正常的生物分布，以及光热成像性能和高对比度荧光图像（信噪比为 14:1）。这些纳米探针在小鼠体内成像的优越性能表明这种探针在实际应用中在高对比度成像和光热治疗方面的巨大潜力。