A Nanoparticle-Based Ratiometric and Self-Calibrated Fluorescent Thermometer for Single Living Cells
A Nanoparticle-Based Ratiometric and Self-Calibrated Fluorescent Thermometer for Single Living Cells
复制标题
DOI：
10.1021/nn405456e
复制
发表时间：
2014-01-01
期刊：
影响因子：
17.1
通讯作者：
Suzuki, Madoka
中科院分区：
文献类型：
--
作者：
Takei, Yoshiaki;Arai, Satoshi;Suzuki, Madoka
体温和能量平衡的动态平衡是生物学的主要原理之一。水溶液的纳米测温是理解这一重要过程的分子基础的一项具有挑战性但又至关重要的技术。在这里，我们开发了一种比率纳米温度计(RNT)，用于实时测量细胞内温度。温度敏感的荧光团，β-二酮螯合物Eu(III)-噻吩甲酰三氟丙酮，和温度不敏感的荧光团，罗丹明101，用作自身参照物，都嵌入在保护荧光团免受细胞内条件影响的聚合物颗粒中。单个RNT斑点的比率测量与RNT沿z轴的位移无关。因此，温度是在光学显微镜下每个RNT的位置确定的，而与活细胞的动态运动无关。作为逐点细胞内测温的演示，我们成功地跟踪了单个细胞中单个RNT点的温度变化以及钙离子载体离子载体离子霉素诱导的钙离子爆发。不同点的温度升高不同，这意味着电池内的热量产生不均匀。然后，我们发现，在某些地点，温度逐渐下降，而在另一些地点，温度保持在较高水平。细胞内平均温升与细胞内Ca~(2+)的增加呈正相关，表明热源的活性和/或数量取决于细胞内的Ca~(2+)浓度。
The homeostasis of body temperature and energy balance is one of the major principles in biology. Nanoscale thermometry of aqueous solutions is a challenging but crucial technique to understand the molecular basis of this essential process. Here, we developed a ratiometric nanothermometer (RNT) for intracellular temperature measurement in real time. Both the thermosensitive fluorophore, beta-diketonate chelate europium(III) thenoyltrifluoroacetonate, and the thermoinsensitive fluorophore, rhodamine 101, which was used as a self-reference, are embedded in a polymeric particle that protects the fluorophores from intracellular conditions. The ratiometric measurement of single RNT spots is independent of the displacement of the RNT along the z-axis. The temperature is therefore determined at the location of each RNT under an optical microscope regardless of the dynamic movement of living cells. As a demonstration of the spot-by-spot intracellular thermometry, we successfully followed the temperature change in individual RNT spots in a single cell together with the Ca2+ burst induced by the Ca2+ ionophore ionomycin. The temperature increases differently among different spots, implying heterogeneous heat production in the cell. We then show that, in some spots, the temperature gradually decreases, while in others it remains high. The average temperature elevation within a cell is positively correlated to the increase in Ca2+, suggesting that the activity and/or number of heat sources are dependent on the Ca2+ concentration.