Photoswitch-modified DNA is being studied for applications including light-harvesting molecular motors, photo-controlled drug delivery, gene regulation, and optically-mediated assembly of plasmonic metal nanoparticles in DNA-hybridization assays. We study the sequence and hybridization dependence of the photoisomerization quantum yield of azobenzene attached to DNA via the popular d-threoninol linkage. Compared to free azobenzene we find that the quantum yield for photoisomerization from trans to cis form is decreased 3-fold when the azobenzene is incorporated into single-stranded DNA, and is further reduced 15-fold for azobenzene incorporated into double-stranded DNA. In addition, we find that the quantum yield is sensitive to the local sequence including both specific mismatches and the overall sequence-dependent melting temperature. These results serve as design rules for efficient photoswitchable DNA sequences tailored for sensing, drug delivery, and energy harvesting applications, while also providing a foundation for understanding phenomena such as photonically controlled hybridization stringency.

Photoisomerization quantum yield of azobenzene-modified DNA depends on DNA sequence

248th National Meeting (2014)

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