Intracellular thermometry techniques play an important role in elucidating the relationship between the intracellular temperature and stem cell functions. However, there have been few reports on thermometry techniques that can detect the intracellular temperature of cells during several days of incubation. In this study, we developed a novel quantum thermometric sensing and analysis system (QTAS) using fluorescent nanodiamonds (FNDs). FNDs could label adipose tissue-derived stem cells (ASCs) at high efficiency with 24 h of incubation, and no cytotoxicity was observed in ASCs labeled with less than 500 μg mL⁻¹ of FNDs. The peak of FNDs was confirmed at approximately 2.87 GHz with the characteristic fluorescence spectra of NV centers that could be optically detected (optically detected magnetic resonance [ODMR]). The ODMR peak clearly shifted to the high-frequency side as the temperature decreased and gave a mean temperature dependence of −(77.6 ± 11.0) kHz °C⁻¹, thus the intracellular temperature of living ASCs during several days of culturing could be precisely measured using the QTAS. Moreover, the intracellular temperature was found to influence the production of growth factors and the degree of differentiation into adipocytes and osteocytes. These data suggest that the QTAS can be used to investigate the relationship between intracellular temperature and cellular functions.

中文翻译：

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一种使用荧光纳米金刚石的量子温度传感和分析系统，用于根据细胞内温度评估活干细胞功能

细胞内测温技术在阐明细胞内温度与干细胞功能之间的关系方面发挥着重要作用。然而，很少有关于温度计技术的报道，可以在几天的孵化过程中检测细胞的细胞内温度。在这项研究中，我们开发了一种使用荧光纳米金刚石 (FND) 的新型量子测温传感和分析系统 (QTAS)。FNDs 可以高效标记脂肪组织来源的干细胞 (ASCs)，孵育 24 小时，并且在标记为小于 500 μg mL ^{-1的 ASCs 中未观察到细胞毒性}的 FND。FND 的峰值在大约 2.87 GHz 处得到证实，具有可以光学检测到的 NV 中心的特征荧光光谱（光学检测磁共振 [ODMR]）。随着温度的降低，ODMR 峰明显向高频侧移动，平均温度依赖性为 -(77.6 ± 11.0) kHz °C ^-1，因此可以精确测量培养几天内活 ASCs 的细胞内温度使用 QTAS。此外，发现细胞内温度影响生长因子的产生以及分化成脂肪细胞和骨细胞的程度。这些数据表明，QTAS 可用于研究细胞内温度和细胞功能之间的关系。