Ultra fast laser pulses for cellular nanosurgery with minimum collateral damage

Abstract

A tightly focused ultra fast laser pulse is an attractive tool for nanosurgery, since at a high enough fluence, tissue ablation occurs through non-linear laser-tissue interactions avalanche ionization seeded by multiphoton ionization. This principle was used in the preliminary experiments, to achieve ablations of size smaller than the light diffraction limit, with single ultra short pulses. A single pulse from an infrared (1054 nm), 700 fs, pulsed laser beam focused by a high numerical aperture objective on the membrane of fixed, dry Chinese hamster ovary cells, yielded the smallest ablation feature size of /spl sim/ 250 nm. However, the nature and extent of collateral damage due to ultra short pulses in vivo remains to be evaluated. A frequency-doubled, 700 fs beam will be focused by the objective of an inverted Zeiss microscope on specific structures in cultured newt lung cells in vivo. To assess the extent of damage, the cells will be fixed, sectioned and observed under a TEM. After characterizing the laser-tissue interaction and the extent of damage, we will apply the ultra short laser as a sophisticated tool for carrying out precise cellular nanosurgery in mitosis related experiments.