Abstract
2',3',5'-Tri-O-acetyl-6,8-dithioguanosine (taDTGuo) is an analogue of nucleosides and currently under investigation as a potential agent for photodynamic therapy (PDT). Excitation by simultaneous two-photon absorption of visible or near-infrared light would provide an efficient PDT for deep-seated tumors. The two-photon absorption spectrum of taDTGuo was obtained by optical-probing photoacoustic spectroscopy (OPPAS). A two-photon absorption band corresponding to the S5 ← S0 transition was observed at 556 nm, and the two-photon absorption cross-section σ(2) was determined to be 26 ± 3 GM, which was much larger than that of other nucleobases and nucleosides. Quantum chemical calculations suggested that the large σ(2) value of taDTGuo was responsible for large transition dipole moments and small detuning energy resulting from the thiocarbonyl group at 6- and 8-positions. This is the first report on two-photon absorption spectra and cross-sections of thionucleoside analogues, which could be used to develop a more specific PDT for cancers in deep regions.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
