title: Two-photon excitation studies of hypocrellins for photodynamic therapy.
abstract: The photophysical and photochemical properties of hypocrellins (HA and HB) are examined with two-photon excitations at 800 nm using femtosecond pulses from a Ti:sapphire laser. The two-photon excited fluorescence spectra of HA and HB are very similar to those obtained by one-photon excitation, which may indicate that the two-photon induced photodynamic processes of hypocrellins are similar to one-photon induced photodynamic processes. The two-photon excitation cross sections of HA and HB are measured at 800 nm as about 34.8 x 10(-50) cm(4) s/photon and 21.3 x 10(-50) cm(4) s/photon, respectively. The large two-photon cross sections of both HA and HB, suggest that the hypocrellins can be potential two-photon phototherapeutic agents. As an example for two-photon photodynamic therapy of hypocrellins, we also further examine the cell-damaging effects of HA upon two-photon illumination. Our preliminary results of cell viability test indicate hypocrellins can effectively damage the Hela cells under two-photon illumination.
authors.affiliation: Center for Molecular Science, Institute of Chemistry, Chinese Academy of Science, Beijing 100080, China.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: Y W
authors.initials: YW
authors.lastname: Zhao
authors.forename: J Q
authors.initials: JQ
authors.lastname: Zhao
authors.forename: A D
authors.initials: AD
authors.lastname: Xia
authors.forename: L J
authors.initials: LJ
authors.lastname: Jiang
authors.forename: S
authors.initials: S
authors.lastname: Wu
authors.forename: L
authors.initials: L
authors.lastname: Ma
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Dong
authors.forename: Y H
authors.initials: YH
authors.lastname: Gu
mesh_terms: D008958:Models, Molecular; D008968:Molecular Conformation; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000627:therapeutic use*; D019800:Phenol; D010778:Photochemotherapy / Q000379:methods*; D017785:Photons / Q000627:therapeutic use*; D017319:Photosensitizing Agents; D011809:Quinones / Q000737:chemistry / Q000627:therapeutic use*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D017319:Photosensitizing Agents; D011809:Quinones; D019800:Phenol; D010569:Perylene; C048388:hypocrellin A; C064522:hypocrellin B