Vibrational photothermal imaging from single molecules to human subjects (Conference Presentation)

Vibrational photothermal (VIP) microscopy opens a new window to look at molecules and molecular interactions inside a biological system including virus, bacterium, cell, and organism. In VIP microscopy, a pump beam excites chemical bonds via mid-infrared absorption, stimulated Raman induced absorption, or shortwave infrared absorption. A probe beam measures the local change of refractive index or thermal expansion of a particle induced by the photothermal effect. Since the first demonstration of mid-infrared photothermal (MIP) imaging of living cells and organisms (Science Adv 2016), our team has advanced this pump-probe chemical imaging technology in three ways, namely scanning-based confocal MIP microscopy, camera-based wide-field MIP microscopy, and computation-based MIP tomography. Since its commercialization into a mIRage system in 2018, MIP microscopy has found broad applications, spanning the analysis of functional materials, characterization of environmental microplastics, and structural detection of protein aggregation in neurological diseases. More recently, we developed stimulated Raman photothermal microscopy (Science Adv 2023) and shortwave infrared photothermal microscopy (Nature Photonics 2024) as new members of VIP microscopy.