Date of Award


Degree Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Kathryn B. Grant


Cyanine dyes are attractive photosensitizers for photodynamic therapy due to their ease of structure modification and intense absorption in the near-infrared range. Photosensitizers that can bind to DNA and absorb at long enough wavelengths of light to deeply penetrate biological tissue are in high demand for treatment of cancer and other diseases. The following study analyzes the DNA interactions of three pentamethine cyanine dyes with very similar structures, all of which absorb light at wavelengths longer than 800 nm. The work described involves an extensive study of the photocleavage abilities and DNA binding characteristics of these dyes. Our lead compound was a bromophenyl meso substituted symmetrical quinoline cyanine dye. Spectroscopic data, gel electrophoresis experiments and other studies were used to provide evidence of DNA binding mode, ROS production, and of dye-sensitized DNA photocleavage at the unprecedented wavelength of 850 nm.