Department of Physics, Boston University, Boston, Massachusetts 02215, United States.
Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, United States.
Anal Chem. 2021 Mar 2;93(8):4100-4107. doi: 10.1021/acs.analchem.0c05333. Epub 2021 Feb 17.
We report a confocal interferometric mid-infrared photothermal (MIP) microscope for ultra-sensitive and spatially resolved chemical imaging of individual viruses. The interferometric scattering principle is applied to detect the very weak photothermal signal induced by infrared absorption of chemical bonds. Spectroscopic MIP detection of single vesicular stomatitis viruses (VSVs) and poxviruses is demonstrated. The single virus spectra show high consistency within the same virus type. The dominant spectral peaks are contributed by the amide I and amide II vibrations attributed to the viral proteins. The ratio of these two peaks is significantly different between VSVs and poxviruses, highlighting the potential of using interferometric MIP microscopy for label-free differentiation of viral particles. This all-optical chemical imaging method opens a new way for spectroscopic detection of biological nanoparticles in a label-free manner and may facilitate in predicting and controlling the outbreaks of emerging virus strains.
我们报告了一种共焦干涉型中红外光热（MIP）显微镜，用于对单个病毒进行超灵敏和空间分辨的化学成像。该干涉散射原理用于检测由化学键红外吸收引起的非常微弱的光热信号。我们演示了对单个水疱性口炎病毒（VSV）和痘病毒的光谱 MIP 检测。同种病毒的单个病毒光谱具有高度一致性。主要光谱峰归因于病毒蛋白的酰胺 I 和酰胺 II 振动。VSV 和痘病毒之间这两个峰的比值有显著差异，突出了使用干涉型 MIP 显微镜对病毒粒子进行无标记区分的潜力。这种全光学化学成像方法为无标记生物纳米粒子的光谱检测开辟了新途径，可能有助于预测和控制新兴病毒株的爆发。
