The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
J Am Chem Soc. 2012 Jun 13;134(23):9565-8. doi: 10.1021/ja302290e. Epub 2012 Jun 1.
Temperature is a key parameter in physiological processes, and probes able to detect small changes in local temperature are necessary for accurate and quantitative physical descriptions of cellular events. Several have recently emerged that offer excellent temperature sensitivity, spatial resolution, or cellular compatibility, but it has been challenging to realize all of these properties in a single construct. Here, we introduce a luminescent nanocrystal-based sensor that achieves this with a 2.4% change/°C ratiometric response over physiological temperatures in aqueous buffers, with a precision of at least 0.2 °C. Thermoresponsive dual emission is conferred by a Förster resonant energy transfer (FRET) process between CdSe-CdS quantum dot-quantum rods (QD-QRs) as donors and cyanine dyes as acceptors, which are conjugated to QD-QRs using an amphiphilic polymer coating. The nanothermometers were delivered to live cells using a pH-responsive cationic polymer colloid, which served to both improve uptake and release nanocrystals from endosomal confinement. Within cells, they showed an unexpected enhancement in their temperature response and sensitivity, highlighting the need to calibrate these and similar probes within the cell.
温度是生理过程中的一个关键参数，能够探测到局部温度微小变化的探针对于准确、定量地描述细胞事件是必要的。最近已经出现了几种具有优异温度灵敏度、空间分辨率或细胞兼容性的探针，但在单个构建体中实现所有这些特性一直具有挑战性。在这里，我们引入了一种基于发光纳米晶体的传感器，它在生理温度范围内的比率响应为 2.4%，在水缓冲液中的精度至少为 0.2°C，实现了这一目标。热响应的双发射是通过 CdSe-CdS 量子点-量子棒 (QD-QR) 作为供体和菁染料作为受体之间的Förster 共振能量转移 (FRET) 过程赋予的，菁染料通过两亲聚合物涂层与 QD-QR 连接。纳米温度计使用 pH 响应性阳离子聚合物胶体递送至活细胞，该胶体既可以提高纳米晶体的摄取率，又可以从内涵体限制中释放纳米晶体。在细胞内，它们表现出出乎意料的温度响应和灵敏度增强，这突出表明需要在细胞内对这些探针和类似探针进行校准。
