A microscope captures 19.2 live-cell chemical volumes each second

A University of Tokyo and RIKEN team built video-rate mid-infrared photothermal optical diffraction tomography. It detects refractive-index changes caused when molecular vibrations absorb mid-infrared light, producing label-free 3D images of chemical components inside living cells. The system accelerates conventional 3D measurement about 400-fold to 19.2 volumes per second. It tracks intracellular lipid droplets through lipid-specific signals and quantifies their motion, while also acquiring 3D spectroscopic images at roughly 20 different wavenumbers within one second. Unlike fluorescence labeling, the method does not add dyes and can repeatedly observe native chemical change, opening a window on metabolism, drug response and organelle dynamics. It remains a laboratory platform: field of view, depth, heating, scattering in complex tissue, instrument cost and data volume could limit clinical or high-throughput use, and performance needs validation across more cells and tissues.