High-Sensitivity Fluorescence Lifetime Thermal Sensing Based on CdTe Quantum Dots
High-Sensitivity Fluorescence Lifetime Thermal Sensing Based on CdTe Quantum Dots
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DOI：
10.1002/smll.201102736
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发表时间：
2012-09-10
期刊：
影响因子：
13.3
通讯作者：
Jaque, D.
中科院分区：
文献类型：
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作者：
Haro-Gonzalez, P.;Martinez-Maestro, L.;Jaque, D.
P. Haro-González， L. Martínez-Maestro, IR . Martín， J. García-Solé，和D. Jaque*传感" .[15]在所有这些方法中，所谓的荧光纳米温度计（FNTs）[11,16 - 18]的使用可能是最有前途的。基本上，fnt是荧光纳米粒子或纳米化合物，其发光（线形、强度或荧光寿命）强烈依赖于温度。由于其特有的纳米尺寸，它们很容易被结合到亚微系统中，这样就可以通过FNTs荧光的局部修饰来检测局部温度分布中的任何奇点在文献中可以找到许多成功用于高分辨率热感测的fnt例子（包括稀土掺杂纳米晶体、半导体纳米晶体、分子温度计和染料化合物）。[16,17,19 - 23]其中，半导体纳米晶体，以下简称量子点（QDs），尤其具有吸引力。众所周知，量子点的发射带强烈依赖于温度，随着温度的升高，同时发生红移和荧光猝灭。[16,20]这些温度诱导的QD荧光带的修饰最初用于集成电路的热成像，现在已经用于监测细胞死亡或产热过程中发生的单细胞温度变化。[11,24,25]在已经被用作FNTs的不同量子点中，CdTe已被证明可以提供最高的热分辨率（超过0.5 C的极限）它们表现出优异的热致红移率，因此通过对其发射带的光谱分析可以实现热传感。尽管过去获得了良好的结果，但该过程需要获得具有高信噪比的QD荧光光谱，以便准确测定峰值波长。这反过来又增加了测量时间（通常是每个点几十秒）。通过对QD荧光寿命的分析进行热读数，即荧光寿命热成像（FLTI）技术，可以克服这种不便。[6,26 - 28]事实上，考虑到CdTe-QDs的荧光寿命为数十纳秒，可以实现超过每秒数百点的读取速率。CdTe-QDs在生物系统中高速、高分辨率FLTI的未来应用需要在生物范围（20-50℃）内CdTe-QDs荧光寿命的明显变化。然而，这一事实尚未得到探讨。因此，CdTe-QDs用于高分辨率FLTI的能力仍然未知。在这项工作中，我们研究了CdTe-QDs荧光寿命在20-50℃生物环境中的变化
P. Haro-González, L. Martínez-Maestro, IR Martín, J. García-Solé, and D. Jaque* sensing”.[15] Among all of them, the use of the so-called fluorescent nano-thermometers (FNTs),[11, 16–18] is, probably, the most promising. Basically, FNTs are fluorescent nano-particles, or nano-compounds, whose luminescence (lineshape, intensity or fluorescence lifetime) are strongly temperature dependent. Due to their characteristic nanometric size, they are easily incorporated in sub-micro systems in such a way that any singularity in the local temperature distribution is detected by a localized modification in the fluorescence of the FNTs.[11] It is possible to find in the literature numerous examples of FNTs successfully used for high-resolution thermal sensing (including rare earth doped nanocrystals, semiconductors nanocrystals, molecular thermometers and dye compounds).[16, 17, 19–23] Among all of them, semiconductor nano-crystals, hereafter quantum dots (QDs), are especially attractive. It is known that the emission band of QDs is strongly dependent on temperature suffering a simultaneous red-shift and fluorescence quenching as the temperature is increased.[16, 20] These temperature induced modifications in the QD fluorescence band, initially used for thermal imaging of integrated circuits, are nowadays already used for monitoring single cell temperature changes taking place during cell’s death or thermogenesis.[11, 24, 25] Among the different QDs that have been already used as FNTs, CdTe have demonstrated to provide the highest thermal resolution (beating the 0.5 C limit).[16] They show an outstanding thermal induced red-shift rate, so that thermal sensing is achieved through the spectral analysis of their emission band. Despite the good results obtained in the past, this procedure requires the acquisition of QD fluorescence spectra with high signal-to-noise ratios so that an accurate determination of the peak wavelength can be done. This, in turns, increases the measuring time (typically tens of seconds per point). This inconvenience would be overcome by performing thermal reading from the analysis of the QD fluorescence lifetime, ie by Fluorescence Lifetime Thermal Imaging (FLTI) techniques.[6, 26–28] Indeed, taking into account that the fluorescence lifetime of CdTe-QDs is of the order of tens of nanoseconds, reading rates in excess of hundreds of points per second could be achieved. The future application of CdTe-QDs for high-speed, highresolution FLTI of biological systems requires an appreciable variation of the CdTe-QDs fluorescence lifetime within the biological range (20–50 C). Nevertheless, this fact has not been yet explored. Therefore, the ability of CdTe-QDs for high-resolution FLTI is still unknown. In this work we have investigated the variation of the CdTe-QDs fluorescence lifetime in the 20–50 C biological