GIANT-CELL FORMATION IN CELLS EXPOSED TO 740-NM AND 760-NM OPTICAL TRAPS

Background and Objective: Optical trapping is becoming a useful and wi despread technique for the micromanipulation of cells and organelles, Giant cell formation following optical trapping was studied to detect the potential adverse effects. Study Design/Materials and Methods: The nuclei of preselected single CHO cells were exposed to 740 nm and 760 nm laser microbeam generated by a titanium-sapphire tunable laser at 88 and 176 mW and different time exposures. The irradiated single cell s were recorded and observed morphologically following exposure. Giant cells were tabulated and photographed. Results: The irradiated cells either failed to divide, or they underwent nuclear proliferation to fo rm giant cells through endoreduplication. Conclusion: Giant cells were induced by both 740 nm and 760 nm. The frequency of giant cell format ion was higher for the longer time exposures and at the higher power d ensities. The use of an optical etalon to remove intracavity mode beat ing and high peak powers of the titanium-sapphire laser caused a signi ficant reduction in the formation of giant cells. (C) 1997 Wiley-Liss, Inc.(dagger)