Ultrasensitive fluorescence-free analysis of nano-matter via Interferometric detection of Scattering (iSCAT): single proteins, viruses, etc.

Abstract

Optical detection of small nanoparticles and single molecules often relies on fluorescence, but limited photophysics and the need for labeling pose severe restrictions for the broad application of this approach. The ubiquitous process of Rayleigh scattering offers a powerful alternative. Although the common intuition might be that detection of individual nanoparticles and single molecules is not within reach via the measurement of their Rayleigh scattering, interferometric scattering (iSCAT) microscopy introduced in 2004 has demonstrated the contrary. In this presentation, I will present the most recent advances in iSCAT analysis, reaching an exquisite sensitivity for detecting single unlabeled proteins as light as 20 kDa. I also discuss results on the detection and microscopy of SARS-Cov-2 viruses in a high-security biosafety environment.