Shining a Light on Mass Photometry

Mass photometry is a technique that uses light to determine the mass of proteins and other biomolecules. When light shines upon amino acids, some of it is deflected in a process known as scattering. The amount of light that scatters is proportional to the number of amino acids present. So, scientists can determine the mass of a protein by measuring the interference between the light scattered by the molecule and the light reflected at the measurement surface. Moreover, the same logic applies to other biologically-related particles, including nucleic acids, vesicles, micelles, and synthetic polymers. Mass photometry is accurate, capable of measuring the mass of a protein to within 2 percent of its true mass. It also possesses a broad dynamic range, spanning two orders of magnitude from tens of kilodaltons to megadaltons. This size range encompasses proteins, protein complexes, DNA, RNA, plasmids, macromolecular complexes, nanostructures, and small viruses such as ...