Optical control of filamentation-induced damage to DNA by intense, ultrashort, near-infrared laser pulses

• DOI: 10.1038/srep27515
• Publication Date: 2016-06-09T09:34:56Z
• Authors: J. A. Dharmadhikari; A. K. Dharmadhikari; K. C. Kasuba; H. Bharambe; J. S. D’Souza; K. D. Rathod; D. Mathur
• Keywords: Filamentation; Numerical aperture; Water window

We report on damage to DNA in an aqueous medium induced by ultrashort pulses of intense laser light 800 nm wavelength. Focusing such pulses, using lenses various focal lengths, induces plasma formation within the medium. Such can have a spatial extent that is far excess Rayleigh range. In case water, resulting ionization and dissociation gives rise situ generation low-energy electrons OH-radicals. Interactions these with plasmid produce nicks backbone: single strand breaks (SSBs) are as are, at higher intensities, double (DSBs). Under physiological conditions, latter not readily amenable repair. Systematic quantification SSBs DSBs different values incident energy under external focusing conditions reveals occurs two distinct regimes. Numerical aperture experimental handle delineates regimes, permitting simple optical control over damage.