Date of Award


Degree Type


Degree Name

Master of Science (MS)



First Advisor

Kathryn B. Grant

Second Advisor

Maged Henary

Third Advisor

Dabney White Dixon


Here we report the DNA photocleavage abilities of near-infrared (NIR) quinolinium pentamethine carbocyanine dyes substituted with either bromine, chlorine, or hydrogen at the meso-carbon position. We are interested in developing these cyanine dyes as treatment agents in photodynamic cancer therapy because they can be activated to selectively kill diseased cells with NIR light that deeply penetrates biological tissues. UV-visible, CD, and fluorescence spectra show that the brominated quinolinium cyanine dyes 4 and KI2 are stable in aqueous buffer and bind to DNA in a non-intercalative manner both externally and in the DNA minor groove. Reactions run in the presence and absence of fluorescent probes and chemical additives reveal that irradiation of dye 4 and KI2 with 707–759-nm and 830-905 nm NIR light respectively generates Type I hydroxyl radicals that form direct strand breaks in plasmid DNA in high yield.


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