Damage-free tip-enhanced Raman spectroscopy for heat-sensitive materials
Damage-free tip-enhanced Raman spectroscopy for heat-sensitive materials
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DOI：
10.1039/c7nr02398g
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发表时间：
2017-08-14
期刊：
影响因子：
6.7
通讯作者：
Hayashi, Tomohiro
中科院分区：
文献类型：
--
作者：
Mochizuki, Masahito;Lkhamsuren, Ganchimeg;Hayashi, Tomohiro
我们报告了一种方法来建立实验条件的针尖增强拉曼光谱（TERS）与低的热和机械损伤的样品。在这种方法中，我们通过TERS光谱监测硫醇分子从原子力显微镜（AFM）的金涂层探针的热脱附。硫醇分子从金表面解吸的温度（60-100摄氏度）涵盖了热敏生物材料（例如蛋白质）降解的温度范围。通过监测探针上硫醇的解吸，我们可以估计激发激光的功率，以使样品达到其热降解的临界温度。此外，我们还发现，原子力显微镜杠杆的主动振荡显着促进从探针到周围介质的热传递。这使得我们能够采用更高功率密度的激发激光器，从而导致与用接触模式获得的信号相比更强的拉曼信号。我们建议，这种组合的方法是有效的，在获得强TERS信号，同时抑制热和机械损伤的软和热敏样品。
We report a method to establish experimental conditions for tip-enhanced Raman spectroscopy (TERS) with low thermal and mechanical damage to samples. In this method, we monitor the thermal desorption of thiol molecules from a gold-coated probe of an atomic force microscope (AFM) via TERS spectra. Temperatures for desorption of thiol molecules (60-100 degrees C) from gold surfaces cover the temperature range for degradation of heat-sensitive biomaterials (e.g. proteins). By monitoring the desorption of the thiols on the probe, we can estimate the power of an excitation laser for the samples to reach their critical temperatures for thermal degradation. Furthermore, we also found that an active oscillation of AFM cantilevers significantly promotes the heat transfer from the probe to the surrounding medium. This enables us to employ a higher power density of the excitation laser, resulting in a stronger Raman signal compared with the signal obtained with a contact mode. We propose that this combinatory method is effective in acquiring strong TERS signals while suppressing thermal and mechanical damage to soft and heat-sensitive samples.