IBIS Lab, Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33647, USA.
Nanoscale. 2016 Dec 7;8(45):18912-18920. doi: 10.1039/c6nr04676b. Epub 2016 Sep 26.
Understanding how plasmonic nanoparticles collectively generate heat upon exposure to light and thus increase the local temperature of the surrounding medium is critical for many applications such as plasmon-assisted microfluidics, plasmonic tweezers, and photothermal cancer therapy. Reliable temperature manipulation requires the capability to spatially and dynamically analyze local temperature profiles as a function of nanoparticle concentration and laser intensity. In this work, we present a novel method for visualization of local temperature increase using elastin-like polypeptides (ELP). We also propose a robust algorithm that allows the construction of reliable calibration curves using known boundary conditions and Boltzmann sigmoid fit applied to the ELP solution's temperature-absorption transfer function. Using this technique, for the first time, we successfully demonstrated how surface and volume distribution of the nano-heaters affect collective heat generation. This approach allows the visualization of dynamic 2D-temperature profiles and simultaneously enables the measurement of specific temperature at any point in a 2D-map. The experimental setup is compatible with conventional optical microscopy and requires no specialized hardware or complex sample preparation. Finally, the real time visualization of plasmonic heating offers an opportunity to control outcomes of thermo-plasmonics which enables a myriad of practical applications.
理解等离子体纳米粒子在暴露于光下时如何集体产生热量，从而增加周围介质的局部温度，对于许多应用至关重要，如等离子体辅助微流控、等离子体镊子和光热癌症治疗。可靠的温度控制需要能够空间和动态地分析局部温度分布作为纳米粒子浓度和激光强度的函数。在这项工作中，我们提出了一种使用弹性蛋白样多肽 (ELP) 可视化局部温度升高的新方法。我们还提出了一种稳健的算法，该算法允许使用已知边界条件和应用于 ELP 溶液的温度吸收传递函数的玻尔兹曼 sigmoid 拟合来构建可靠的校准曲线。使用该技术，我们首次成功地证明了纳米加热器的表面和体积分布如何影响集体热生成。这种方法允许可视化动态 2D 温度分布，并同时能够在 2D 图谱中的任何点测量特定温度。实验装置与传统的光学显微镜兼容，不需要特殊的硬件或复杂的样品制备。最后，等离子体加热的实时可视化提供了控制热等离子体结果的机会，从而实现了无数的实际应用。
