Three-dimensional laser microsurgery in light-sheet based microscopy (SPIM).

Advances in the life sciences rely on the ability to observe dynamic processes in live systems and in environments that mimic in-vivo situations. Therefore, new methodological developments have to provide environments that resemble physiologically and clinically relevant conditions as closely as possible. In this work, plasma-induced laser nanosurgery for three-dimensional sample manipulation and sample perturbation is combined with optically sectioning light-sheet based fluorescence microscopy (SPIM) and applied to three-dimensional biological model systems. This means: a) working with a biological system that is not confined to essentially two dimensions like cell cultures on cover glasses, b) gaining intrinsic optical sectioning capabilities by an efficient three-dimensional fluorescence imaging system, and c) using arbitrarily-shaped three-dimensional ablation-patterns by a plasma-induced laser ablation system that prevent damage to surrounding tissues. Spatial levels in our biological applications range from sub-microns during delicate ablation of single microtubules over the confined disruption of cell membranes in an MDCK-cyst to the macroscopic cutting of a millimeter-sized Zebrafish caudal fin with arbitrary three-dimensional ablation patterns. Dynamic processes like laser-induced hemocyte migration can be studied with our SPIM-microscalpel in intact, live embryos.