Super-Resolution Nonlinear Photothermal Microscopy
Super-Resolution Nonlinear Photothermal Microscopy
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DOI：
10.1002/smll.201300024
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发表时间：
2014-01-15
期刊：
影响因子：
13.3
通讯作者：
Zharov, Vladimir P.
中科院分区：
文献类型：
--
作者：
Nedosekin, Dmitry A.;Galanzha, Ekaterina I.;Zharov, Vladimir P.
超分辨率荧光显微镜能够成像超过衍射极限的荧光结构。然而，这种技术不能应用于弱荧光细胞成分或标记。作为一种替代方法，基于吸收能量的非辐射转化为热的光热显微镜已经证明了包括单分子和类似于1纳米金纳米颗粒的非荧光结构的成像。然而，以前的光热成像仅在衍射限制的分辨率下进行。本文介绍了基于非线性信号依赖于激光能量的超分辨率远场光热显微镜。在各种非线性现象中，包括吸收饱和、多光子吸收和信号温度依赖，激光诱导纳米气泡在过热纳米物体周围放大信号。使用高斯激光束剖面来演示校准的260纳米金属条的图像空间锐化，等离子体纳米组件的分辨率，石墨烯中10纳米金纳米粒子的可视化以及活红细胞中血红蛋白纳米团簇的分辨率低至50纳米。这些非线性现象可以用于三维成像与提高横向和轴向分辨率在大多数光热方法，包括光声显微镜。
Super-resolution fluorescence microscopy enables imaging of fluorescent structures beyond the diffraction limit. However, this technique cannot be applied to weakly fluorescent cellular components or labels. As an alternative, photothermal microscopy based on nonradiative transformation of absorbed energy into heat has demonstrated imaging of nonfluorescent structures including single molecules and similar to 1-nm gold nanoparticles. However, previously photothermal imaging has been performed with a diffraction-limited resolution only. Herein, super-resolution, far-field photothermal microscopy based on nonlinear signal dependence on the laser energy is introduced. Among various nonlinear phenomena, including absorption saturation, multiphoton absorption, and signal temperature dependence, signal amplification by laser-induced nanobubbles around overheated nano-objects is explored. A Gaussian laser beam profile is used to demonstrate the image spatial sharpening for calibrated 260-nm metal strips, resolving of a plasmonic nanoassembly, visualization of 10-nm gold nanoparticles in graphene, and hemoglobin nanoclusters in live erythrocytes with resolution down to 50 nm. These nonlinear phenomena can be used for 3D imaging with improved lateral and axial resolution in most photothermal methods, including photoacoustic microscopy.