In one of the many proverbial past lives of this author, I worked on research to help advance the technology of optical tweezers. In particular, I worked with my research group at Illinois Wesleyan University in collaboration with the University of Chicago to develop the first holographic optical element that patterned a laser beam into a pre-defined organization of focused spots, each of which successfully trapped microscopic particles. This work on Holographic Optical Traps (HOTs) actually lead to the commercialization of the technology at Arryx, Inc.
The beauty of the creation of optical traps with focused laser light is that if the correct wavelength is selected, then biological material–in particular, neurons–won’t absorb the light, heat up and die. They can, however, still feel the forces resulting from the changing electromagnetic field as the laser beam focuses and de-focuses through the cell.
So, neurons are interconnected by complicated networks. There is some sort of structural pattern to this network, albeit the specifics of this structure remain unknown and not well understood. But, if we want to create devices that integrate networked neurons on computer chips, then we might want to be able to have a high degree of control in patterning the cells’ positions so they network together such that they may communicate in powerful ways, yet also connect efficiently to pre-fabricated electrodes through which a computer might actually record and control their electrical activity.
An optical tweezer as a non-invasive, but fully patternable positioning device is then certainly an intriguing tool that could prove quite useful in the future field of neurotechnology. A research group at St. Andrews University has recently tested a simple line optical tweezer and is currently studying its affects on how it might direct the growth cones of developing neurons.
The fundamental mechanism of how the cells react to the focused laser light is not yet known, but there is an observed interaction. The current observation is that the forces resulting from the focusing and defocusing laser light is providing a torque force on the filopedia–the tiny protrusions that guide the growth cones of a neuron’s axon–and direct them to line up with the path of the line optical trap.
Check out this exciting research, and envision how it can someday be quite influential in the capabilities of neurotechnologies. We’ll be closing watching the developments here from Neuron News.
“Lasers guide neuron growth” :: optics.org :: July 21, 2008 :: [ READ ]
“Guided neuronal growth using optical line traps” D. J. Carnegie, D. J. Stevenson, M. Mazilu, F. Gunn-Moore, and K. Dholakia, Optics Express Volume 16, Issue 14, pp. 10507-10517 (2008) :: [ READ THE ABSTRACT ], which includes a link to read the full text of the research article.