Photo-Induced Cell Damage Analysis for Single-and Multifocus Coherent Anti-Stokes Raman Scattering Microscopy

In this study,we investigated photo-induced damage to living cells during single-and multifocus excitations for coherent anti-stokes raman scattering (cars) imaging. a near-infrared pulsed laser (709 nm) was used to induce cell damage. we compared the photo-induced cell damage in the single-and the multifocus excitation schemes with the condition to obtain the same cars signal in the same frame rate. for the evaluation of cell viability,we employed 4′,6-diamidino-2-phenylindole (dapi) fluorophores that predominantly stained the damaged cells. one-and two-photon fluorescence of dapi fluorophores were,respectively,excited by an ultraviolet light source and the same near-infrared light source and were monitored to evaluate the cell viability during near-infrared pulsed laser irradiation. we found lower uptake of dapi fluorophores into hela cells during the multifocus excitation compared with the single-focus excitation scheme in both the one-and the two-photon fluorescence examinations. this indicates a reduction of photo-induced cell damage in the multifocus excitation. our findings suggested that the multifocus excitation scheme is expected to be suitable for cars microscopy in terms of minimal invasiveness. © 2017 takeo minamikawa et al.