Optical knock out of stem cells with extremely ultrashort femtosecond laser pulses

Novel ultracompact multiphoton. sub-20 femtosecond near infrared 85MHz laser scanning microscopes and conventional 250 fs laser microscopes have been used to perform, high spatial resolution two-photon imaging of stem cell clusters as well, as selective-,int.l.lacellula,r nanoprocessing and knock out of living single stem cells within an 3D microenvironment without any collateral damage. Also lethal, cell exposure of large, parts of cell clusters was successfully probed while maintaining single cells of interest alive. The mew power could be kept in the milliwatt range for 3D nanoprocessing and even in the microwatt range for two-photon imabing. Ultracompact low power sub-20 fs laser systems may becone interesting tools for optical nanobiotechnology such as optical cleaning of stem clusters as well as optical transfection. [GRAPHICS] Optical knock out of a single human pancreatic stem cell without collateral damage.