Label-free transient absorption imaging of cultured fibroblasts

Transient absorption has the potential to probe sub-cellular mitochondrial heterogeneity and reveal complementary but different information from widely-used fluorescence techniques. Here, we report on imaging results in live, cultured human fibroblasts, with visible-wavelength, ⁓300 femtosecond pump (520 nm) and probe (620 nm). Analysis of delay stacks with singular value decomposition reveals redox-dependent changes in picosecond transient lifetimes that were subtle when compared with the pronounced changes observed in muscle fibers.