Intracellular nanosurgery with near infrared femtosecond laser pulses.

We report on laser-assisted knocking out of genomic nanometer-sized regions within the nucleus of living cells. The intranuclear nanosurgery was possible by application of highly intense near infrared femtosecond laser pulses. The non-contact laser treatment was performed within a closed sterile cell chamber. The destructive multiphoton effect was based on 10(12) W/cm2 light intensities and limited to a sub-femtoliter focal volume of a high numerical aperture objective. We used the intracellular nanoscalpel for highly precise non-contact dissection of Hoechst-labelled chromosomes within a nucleus of a living Chinese hamster ovary cell. Following laser treatment, the cell remained alive and did not show any signs of membrane perturbation. The use of near infrared pulses provide the possibility of non-invasive intracellular nanoprocessing also within living tissue in depths of more than 100 microns.