Noncontact optical nanothermometers operating within the biological transparency windows are required to study temperature-sensitive biological phenomena at the nanoscale. Nanoparticles containing rare-earth ions such as Nd³⁺ have been reported to be efficient luminescence-based ratiometric thermometers, however often limited by poor water solubility and concentration-related quenching effects. Herein, we introduce a new type of nanothermometer, obtained by employing low-dimensional carbon nanodots (CNDs) as matrices to host Nd³⁺ ions (NdCNDs). By means of a one-pot procedure, small (∼7–12 nm), water-soluble nanoparticles were obtained, with high (15 wt %) Nd³⁺ loading. This stable metal-CND system features temperature-dependent photoluminescence in the second biological window (BW II) upon irradiation at 808 nm, thereby allowing accurate and reversible (heating/cooling) temperature measurements with good sensitivity and thermal resolution. The system possesses remarkable biocompatibility in vitro and promising performance at a high penetration depth in tissue models.

中文翻译：

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用于纳米测温的 Nd3+ 掺杂碳纳米点的温度依赖性发光


需要在生物透明窗口内运行的非接触式光学纳米温度计来研究纳米尺度的温度敏感生物现象。据报道，含有稀土离子（例如 Nd ³⁺ ）的纳米颗粒是有效的基于发光的比例温度计，但常常受到水溶性差和浓度相关猝灭效应的限制。在此，我们介绍了一种新型纳米温度计，它是通过采用低维碳纳米点（CND）作为基质来承载 Nd ³⁺ 离子（NdCND）而获得的。通过一锅法，获得了小（~7-12 nm）水溶性纳米颗粒，具有高（15 wt%）Nd ³⁺ 负载量。这种稳定的金属-CND 系统在 808 nm 照射下在第二生物窗口 (BW II) 中具有与温度相关的光致发光特性，从而可以实现精确且可逆（加热/冷却）的温度测量，并具有良好的灵敏度和热分辨率。该系统在体外具有显着的生物相容性，并且在组织模型中具有高渗透深度的良好性能。