Standard-unit measurement of cellular viability using dynamic light scattering optical coherence microscopy.

Dynamic light scattering optical coherence microscopy (DLS-OCM) integrates DLS, which measures diffusion or flow of particles by analyzing fluctuations in light scattered by the particles, and OCM, which achieves single-cell resolution by combining coherence and confocal gating, integratively enabling cellular-resolution 3D mapping of the diffusion coefficient, and flow velocity. The diffusion coefficient mapping has a potential for the non-destructive measurement of cellular viability in the standard unit but has not been validated yet. Here, we present DLS-OCM imaging of intra-cellular motility (ICM) as a surrogate of cellular viability. For this purpose, we have simultaneously obtained and compared ICM-contrast DLS-OCM images and calcium fluorescence-contrast images of retinal ganglion cells, and then characterized the responses of the measured ICM to a change in cellular viability induced by environmental conditions such as temperature and pH. The diffusion-coefficient-represented ICM exhibits consistent changes with the manipulated cellular viability.