Microsurgery of Cell Membrane with Femtosecond Laser Pulses for Cell Fusion and Optical Injection

We report on results of using femtosecond laserscalpel for microsurgery of plasma membrane ofliving cells. Femtosecond laser pulses were appliedto initiate cell fusion as well as to performreversible permeabilization of cell membranerequired for efficient injection of extrinsicsubstances into the target cells. Laser-based cellfusion of mammalian embryo blastomeres as wellas fusion of cell bodies of neurons of molluskLymnaea stagnalis were successfully carried out byapplying single femtosecond laser pulses (secondharmonic of a Cr:Forsterite laser system) 620 nm,100 fs with the fluences of 0.42-0.71 J/cm2. It wasshown that the fusion of cells was completed within5-60 minutes depending on the cell type. Successfulpermeabilization of a cell membrane andoptoinjection of a membrane impermeable dye wasperformed with the help of a compact laser systemfor cell microsurgery DissCell-F (ytterbium laser,1050 nm, 75 MHz, ~115 fs). In both cases the laserirradiation parameters were thoroughly optimized toachieve high viability of treated cells and highefficiency of the procedures of cell fusion andoptical injection.