Practice question

Direct stochastic optical reconstruction microscopy belongs to single-molecule localization super-resolution methods. It relies on photoswitchable or photoactivatable fluorophores that transiently flip between dark and bright states in special buffers. At any moment only a sparse subset emits, so individual point spread functions do not overlap and can be fitted with nanometer precision. Thousands of frames accumulate localizations building a composite super-resolved image with 20-nanometer resolution. This blinking behavior enables resolving nucleosome arrangements, membrane receptors and viral assembly intermediates invisible to conventional fluorescence optics.