Sub-diffraction imaging with confocal fluorescence microscopy by stochastic photobleaching

We propose a single molecule localization method which takes advantage of stochastic photobleaching to improve the resolution of confocal fluorescence microscopy. By detecting the stochastic intensity loss of fluorophores, each fluorophore in the field can be localized. When all locations are known, a sub-diffraction image can be retrieved through single molecule localization algorithms. A confocal scheme is used to record the bleaching process of the sample. Each fluorophore can be localized from the recorded streaming followed by image subtraction. Compared with other single molecule localization concepts such as stochastic optical reconstruction microscopy (STORM) and photoactivated localization microscopy (PALM), this method does not require a laser cycling equipment and the pixel size is no longer limited by the size of CCD. This technique works well with common fluorescent dyes and does not require the use of engineered photoactivatable proteins or photoswitchable synthetic dye pairs.