Fluorescence Imaging Group, Departamento de Física de Materiales, C-IV, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
Nano Lett. 2010 Dec 8;10(12):5109-15. doi: 10.1021/nl1036098. Epub 2010 Nov 9.
The technological development of quantum dots has ushered in a new era in fluorescence bioimaging, which was propelled with the advent of novel multiphoton fluorescence microscopes. Here, the potential use of CdSe quantum dots has been evaluated as fluorescent nanothermometers for two-photon fluorescence microscopy. In addition to the enhancement in spatial resolution inherent to any multiphoton excitation processes, two-photon (near-infrared) excitation leads to a temperature sensitivity of the emission intensity much higher than that achieved under one-photon (visible) excitation. The peak emission wavelength is also temperature sensitive, providing an additional approach for thermal imaging, which is particularly interesting for systems where nanoparticles are not homogeneously dispersed. On the basis of these superior thermal sensitivity properties of the two-photon excited fluorescence, we have demonstrated the ability of CdSe quantum dots to image a temperature gradient artificially created in a biocompatible fluid (phosphate-buffered saline) and also their ability to measure an intracellular temperature increase externally induced in a single living cell.
量子点的技术发展开创了荧光生物成像的新时代，新型多光子荧光显微镜的出现推动了这一发展。在这里，我们评估了 CdSe 量子点作为用于双光子荧光显微镜的荧光纳米温度计的潜力。除了任何多光子激发过程固有的空间分辨率提高之外，双光子（近红外）激发导致发射强度的温度灵敏度比单光子（可见）激发下的温度灵敏度高得多。峰值发射波长也对温度敏感，为热成像提供了另一种方法，这对于纳米粒子不均匀分散的系统特别有趣。基于双光子激发荧光的这种优越的热灵敏度特性，我们已经证明了 CdSe 量子点能够对在生物相容性流体（磷酸盐缓冲盐水）中人为创建的温度梯度进行成像，并且还能够测量单个活细胞外部诱导的细胞内温度升高。
