Monitoring cell survival after extraction of a single subcellular organelle using optical trapping and pulsed-nitrogen laser ablation

This paper characterizes cell viability in three different cell lines-Chinese hamster ovary cells (CHO), neuroblastoma cells fused with glialoma cells (NG108-15) and murine embryonic stem cells (ES-D3)-after N-2 laser disruption of the cell membrane and removal, via optical trapping, of a single subcellular organelle. Morphological changes and viability (as determined by live/dead fluorescent stains) of the cell were monitored every half hour over a 4-h period postsurgery. The ability of the cell to survive organelle extraction was found to depend both on the conditions under which surgery was performed and on the cell type. The average viability after surgery for CHO cells was approximately 80%, for NG 108 cells it was approximately 30% and for ES-D3 cells postsurgery viability was approximately 10%. From over 600 surgeries we found the survival of the cell is determined almost exclusively within the first hour postsurgery regardless of cell line. The optimal pulse energy for N-2 laser ablation was approximately 0.7 mu J. The N-2 pulse produced an approximately 1-3 mu m hole in the cell membrane and proved to be the primary source of cell death in those cells that did not survive the procedure.