By a News Reporter-Staff News Editor at Physics Week -- Current study results on Biophysics have been published. According to news originating from La Jolla, California, by VerticalNews correspondents, research stated, "Time-resolved imaging, fluorescence microscopy, and hydrodynamic modeling were used to examine cell lysis and molecular delivery produced by picosecond and nanosecond pulsed laser microbeam irradiation in adherent cell cultures. Pulsed laser microbeam radiation at lambda = 532 nm was delivered to confluent monolayers of PtK2 cells via a 40x, 0.8 NA microscope objective."
Our news journalists obtained a quote from the research from the University of California, "Using laser microbeam pulse durations of 180-1100 ps and pulse energies of 0.5-10.5 mu J, we examined the resulting plasma formation and cavitation bubble dynamics that lead to laser-induced cell lysis, necrosis, and molecular delivery. The cavitation bubble dynamics are imaged at times of 0.5 ns to 50 mu s after the pulsed laser microbeam irradiation, and fluorescence assays assess the resulting cell viability and molecular delivery of 3 kDa dextran molecules. Reductions in both the threshold laser microbeam pulse energy for plasma formation and the cavitation bubble energy are observed with decreasing pulse duration. These energy reductions provide for increased precision of laser-based cellular manipulation including cell lysis, cell necrosis, and molecular delivery. Hydrodynamic analysis reveals critical values for the shear-stress impulse generated by the cavitation bubble dynamics governs the location and spatial extent of cell necrosis and molecular delivery independent of pulse duration and pulse energy. Specifically, cellular exposure to a shear-stress impulse J greater than or similar to 0.1 Pa s ensures cell lysis or necrosis, whereas exposures in the range of 0.035 less than or similar to J less than or similar to 0.1 Pa s preserve cell viability while also enabling molecular delivery of 3 kDa dextran. Exposure to shear-stress impulses of J less than or similar to 0.035 Pa s leaves the cells unaffected. Hydrodynamic analysis of these data, combined with data from studies of 6 ns microbeam irradiation, demonstrates the primacy of shear-stress impulse in determining cellular outcome resulting from pulsed laser microbeam irradiation spanning a nearly two-orders-of-magnitude range of pulse energy and pulse duration."
According to the news editors, the research concluded: "These results provide a mechanistic foundation and design strategy applicable to a broad range of laser-based cellular manipulation procedures."
For more information on this research see: Hydrodynamic Determinants of Cell Necrosis and Molecular Delivery Produced by Pulsed Laser Microbeam Irradiation of Adherent Cells. Biophysical Journal, 2013;105(9):2221-2231. Biophysical Journal can be contacted at: Cell Press, 600 Technology Square, 5TH Floor, Cambridge, MA 02139, USA. (Elsevier - www.elsevier.com; Biophysical Journal - www.elsevier.com/wps/product/cws_home/716950)
The news correspondents report that additional information may be obtained from J.L. Compton, University of California, Dept. of Bioengn, La Jolla, CA 92093, United States. Additional authors for this research include A.N. Hellman and V. Venugopalan.
Keywords for this news article include: La Jolla, California, Biophysics, United States, North and Central America
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