Analysis of Heat Affected Zone during Short Pulse Laser Cellular Interrogation Using Fiberoptic Nanobiosensors

Analysis of Heat Affected Zone during Short Pulse Laser Cellular Interrogation Using Fiberoptic Nanobiosensors
Sponsor: National Science Foundation

The propagation of light into tissue and its absorption and utilization is currently a poorly understood process. These processes are important for low intensity laser therapy, a technology used by much of the world, but only receiving limited FDA approval in the Unites States. The objective of this research is to design fiber-optic based nano-probes for precise delivery of laser light and for probing desired cellular organelles and study the mechanism of light interaction during low-level laser irradiations of tissues. Nano-probes are produced by drawing or etching the optical fiber tips to submicron size using a micro-puller or hydrofluoric acid bath. Then the fiber tip is coated with metal to minimize the leakage of light through fiber cladding. Various cell lines have been purchased from vendors and incubated. Laser and LED wavelengths are precisely delivered to different parts of the cell using a fiber nano-probe and the output fluorescence signals from target location is sensed by another fiber nano-probe which is connected to a fluorescent lifetime imaging microscope or photon counter for real-time measurements. Parametric studies have been performed with variation of laser power, wavelength and exposure time. Cells and cellular organelles are found to respond to light in a number of ways including rate of cell division, formation of singlet oxygen, and generation of ATP depending upon the light parameters and target location of laser beam. This direct method avoids the use of complex dyes and fluorescence methods subject to variable and unspecific results.

Publications:

Pal, G., Dutta, A., Mitra, K., Grace, M., Amat, A., Romanczk, T., Wu, X., Chakrabarti, K., and Anders, J., Gorman, E., Waynant, R.W., Tata, D., “ Effect of Low Intensity Laser Interaction with a Human Skin Fibroblast Cell usi,” , Vol. 86, pp. 252-261 (2007).

Pal, G., Dutta, A., Mitra, K., Grace, M., Ilev, I., Waynant, R.W., and Anders, J., “Fluorescence Life Time Imaging from Neurons and Organelles during Low Intensity Laser Therapy using Fiber-Optic Nano-Probes,” American Society for Laser Medicine and Surgery Annual Meeting, Boston (Massachusetts), April 5-April 7 (2006).