Optical trapping and manipulation of single cells using infrared laser beams

The use of infrared light to make improved laser traps with significantly less optical damage to a variety of living cells is reported. IR light was used to observe the reproduction of E. coli within optical traps at power levels sufficient to manipulate at velocities up to about 5000 micron/s. Reproduction of yeast cells by budding was also achieved in IR traps capable of manipulating individual cells and clumps of cells at velocities of about 100 microns/s. Damage-free trapping and manipulation of suspensions of human red blood cells and organelles within individual living cells of spirogyra was also achieved. The manipulative capabilities of optical techniques were exploited in experiments showing separation of individual bacteria from one sample and their introduction into another sample. Optical orientation of individual bacterial cells in space was also achieved using a pair of laser-beam traps.