Two-photon excitation studies of m-THPC photosensitizer and photodynamic activity in an epithelial cell line

M Atif; P E Dyer; T A Paget; H V Snelling; M R Stringer

doi:10.1016/j.pdpdt.2006.10.004

Two-photon excitation studies of m-THPC photosensitizer and photodynamic activity in an epithelial cell line

Photodiagnosis Photodyn Ther. 2007 Jun;4(2):106-11. doi: 10.1016/j.pdpdt.2006.10.004. Epub 2006 Dec 11.

Authors

M Atif¹, P E Dyer², T A Paget³, H V Snelling², M R Stringer⁴

Affiliations

¹ Department of Physics, University of Hull, Hull HU6 7RX, UK; Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
² Department of Physics, University of Hull, Hull HU6 7RX, UK.
³ Department of Biology, University of Hull, Hull HU6 7RX, UK.
⁴ Institute of Microwaves and Photonics, University of Leeds, UK.

PMID: 25047343
DOI: 10.1016/j.pdpdt.2006.10.004

Abstract

A femtosecond laser delivering pulses of wavelength 800nm and 124fs duration at rates of 1kHz has been used to investigate the two-photon excited fluorescence in the photosensitizer m-THPC. The scaling of fluorescence amplitude with laser power and fluorescence sidelight imaging are found to support a predominantly two-photon excitation mechanism. A value for the two-photon cross-section of δ=1.8×10(-57)m(4)s is derived by comparing the fluorescence signals excited by wavelengths of 800 and 400nm. Preliminary results demonstrating the two-photon induced PDT activity of m-THPC in an epithelial cell line are also reported.