Enhanced delivery of molecules into cells using laser-induced stress waves

This study investigated the ability of laser-induced stress waves to enhance delivery of molecules into cells. Our experiment involved irradiating a thin layer of gel containing India ink at the tip of a capillary tube containing cells. The laser pulses (10 ns, 532 nm) deposited energy in the gel layer and generated intense stress waves which propagated into the capillary tube and affected the cells. The gel surface of irradiation was open to the air therefore the boundary condition was a free surface. The cell medium contained fluorescein attached to dextran of various molecular weights. After repeated laser pulses, the cells were collected on a glass slide and observed by fluorescence microscopy. Irradiated cells were observed to have taken up dye relative to unirradiated controls. The results indicate the ability of stress waves to enhance the uptake of large molecular weight reagents by cells.