Photothermal Microscopy and
Spectroscopy Webinar

Fundamental limitations of fluorescence imaging have motivated many groups to develop fluorescence-free methods. Among various contrast mechanisms, scattering offers unique opportunities. About two decades ago, we showed that single gold nanoparticles as small as 5 nm could be detected via interferometric detection of their scattering, coined iSCAT. Since then, it has been shown that unlabeled nano-objects such as viruses and proteins as small as 10 kDa can be detected, weighed, counted and tracked.

iSCAT is a homodyne technique based on the interference of the light scattered from a nano-object with a reference light, e.g., reflected from the sample substrate. Recently, we demonstrated that confocal iSCAT not only addresses the coherent background challenge that arises in live cell imaging, but it also offers label-free 3D images of intracellular organelles at the nanoscale. In this presentation, we show how confocal iSCAT microscopy exploits information about the material, size, shape and axial position of a nano-object to image a range of organelles and subcellular features, including mitochondria, focal adhesion points, endoplasmic reticulum networks, lipid droplets, lysosomes and microtubules. The technique presents a new powerful addition to the microscopy toolbox, can be easily implemented on existing commercial instruments and be carried out simultaneously with fluorescence microscopy.