Healing With Light? Optical Technology Controls Living Cells

For years, scientists have used the energy in laser light to drill microscopic holes or as tweezers or traps to direct and maneuver small pieces of matter. Guiding entire cells, though, has proven difficult because the lasers used for manipulation tend to damage the structural units of living organisms.

Now Aristide Dogariu and colleagues at the University of Central Florida in Orlando have developed an optical procedure that does not harm cells, but affects their skeletons – an ensemble of slender rods made out of an abundant protein called actin. The actin rods are constantly growing and shrinking inside of cells. The direction in which they grow changes the cell's membrane shape and dictates where the cell moves.

Dogariu and colleagues use the polarization of optical waves to create a field around the cells in which the growing actin rods line up like a compass in the Earth's magnetic field. These optical fields can be used to guide large groups of cells to line up and move in the same direction.

The technique could be useful for cancer assays, which test the motility of cells, or as a non-invasive, non-toxic boost for regenerative medicine. Though cells have complicated and intriguing mechanisms to sense and communicate where an injury occurs, the possibility of using photonic scaffolds to stimulate and guide cells' motility to accelerate tissue repair, is now quite promising.

This research is scheduled to be presented during the 2009 Conference on Lasers and Electro-Optics/International Quantum Electronics Conference (CLEO/IQEC) May 31 to June 5 at the Baltimore Convention Center in Baltimore.