This paper is part of a special issue dedicated to Professor J. C. (Tito) Scaiano on the occasion of his 60th birthday.
5,10,15,20-Tetrakis(N-Methyl-4-Pyridyl)-21 H,23H-Porphine (TMPyP) as a Sensitizer for Singlet Oxygen Imaging in Cells: Characterizing the Irradiation-dependent Behavior of TMPyP in a Single Cell†
Article first published online: 30 APR 2007
Photochemistry and Photobiology
Volume 82, Issue 1, pages 177–184, January 2006
How to Cite
Snyder, J. W., Lambert, J. D. C. and Ogilby, P. R. (2006), 5,10,15,20-Tetrakis(N-Methyl-4-Pyridyl)-21 H,23H-Porphine (TMPyP) as a Sensitizer for Singlet Oxygen Imaging in Cells: Characterizing the Irradiation-dependent Behavior of TMPyP in a Single Cell. Photochemistry and Photobiology, 82: 177–184. doi: 10.1562/2005-05-30-RA-553
- Issue published online: 30 APR 2007
- Article first published online: 30 APR 2007
- Received 30 May 2005; accepted 8 December 2005; published online 13 December 2005
Singlet molecular oxygen, a1Δg, can be detected from a single cell by its weak 1270 nm phosphorescence (a1ΔgΔX3Σg-) upon irradiation of the photosensitizer 5,10,15,20-tetrakis (N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) incorporated into the cell. The behavior of this sensitizer in a cell, and hence the behavior of the associated singlet oxygen phosphorescence signal, depends on the conditions under which the sample is exposed to light. Upon irradiation of a neuron freshly incubated with TMPyP, the intensity of TMPyP fluorescence initially increases and there is a concomitant increase in the singlet oxygen phosphorescence intensity from the cell. These results appear to reflect a photoinduced release of TMPyP bound to DNA in the nucleus of the cell, where TMPyP tends to localize, and the subsequent relocalization of TMPyP to a different microenvironment in the cell. Upon prolonged irradiation of the cell, TMPyP photobleaches and there is a corresponding decrease in the singlet oxygen phosphorescence intensity from the cell. The data reported herein provide insight into key factors that can influence photosensitized singlet oxygen experiments performed on biological samples.