19 November 2012 Carcinogenic damage to deoxyribonucleic acid is induced by near-infrared laser pulses in multiphoton microscopy via combination of two- and three-photon absorption
Author Affiliations +
Abstract
Nonlinear optical imaging modalities (multiphoton excited fluorescence, second and third harmonic generation) applied in vivo are increasingly promising for clinical diagnostics and the monitoring of cancer and other disorders, as they can probe tissue with high diffraction-limited resolution at near-infrared (IR) wavelengths. However, high peak intensity of femtosecond laser pulses required for two-photon processes causes formation of cyclobutane-pyrimidine-dimers (CPDs) in cellular deoxyribonucleic acid (DNA) similar to damage from exposure to solar ultraviolet (UV) light. Inaccurate repair of subsequent mutations increases the risk of carcinogenesis. In this study, we investigate CPD damage that results in Chinese hamster ovary cells in vitro from imaging them with two-photon excited autofluorescence. The CPD levels are quantified by immunofluorescent staining. We further evaluate the extent of CPD damage with respect to varied wavelength, pulse width at focal plane, and pixel dwell time as compared with more pronounced damage from UV sources. While CPD damage has been expected to result from three-photon absorption, our results reveal that CPDs are induced by competing two- and three-photon absorption processes, where the former accesses UVA absorption band. This finding is independently confirmed by nonlinear dependencies of damage on laser power, wavelength, and pulse width.
© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)
Oleg Nadiarnykh, Oleg Nadiarnykh, Giju Thomas, Giju Thomas, Johan van Voskuilen, Johan van Voskuilen, Henricus J. Sterenborg, Henricus J. Sterenborg, Hans C. Gerritsen, Hans C. Gerritsen, } "Carcinogenic damage to deoxyribonucleic acid is induced by near-infrared laser pulses in multiphoton microscopy via combination of two- and three-photon absorption," Journal of Biomedical Optics 17(11), 116024 (19 November 2012). https://doi.org/10.1117/1.JBO.17.11.116024 . Submission:
JOURNAL ARTICLE
7 PAGES


SHARE
Back to Top