title: Two-photon absorption cross-sections and time-resolved fluorescence imaging using porphyrin photosensitisers.
abstract: Three porphyrin systems have been characterised for use in two-photon fluorescence imaging of biological samples. We have determined the two-photon absorption cross sections (sigma(2)) of the di-cation, free-base and metallated forms of hematoporphyrin derivative (HpD), hematoporphyrin IX (Hp9) and a boronated protoporphyrin (BOPP) using the open-aperture Z-scan and the two-photon induced fluorescence (TPIF) techniques at an excitation wavelength of 800 nm. The insertion of either protons or a metal ion into the macrocycle is shown not to significantly influence the sigma(2) of the porphyrins. Two-photon time-resolved fluorescence images of C6 glioma cells transfected with a free-base form of the BOPP have been obtained as a function of the porphyrin concentration. These studies reveal a maximum useful porphyrin concentration for fluorescence imaging purposes of approximately 30 microg mL(-1).
authors.affiliation: School of Chemistry, The University of Melbourne, Victoria, 3010, Australia.
authors.forename: Sean
authors.initials: S
authors.lastname: Mathai
authors.forename: Damian K
authors.initials: DK
authors.lastname: Bird
authors.forename: Stan S
authors.initials: SS
authors.lastname: Stylli
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Smith
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Ghiggino
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D015394:Molecular Structure; D017785:Photons; D017319:Photosensitizing Agents / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D051381:Rats; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins