Pg. Spizzirri et al., PHOTOPHYSICS AND INTRACELLULAR-DISTRIBUTION OF A BORONATED PORPHYRIN PHOTOTHERAPEUTIC AGENT, Photochemistry and photobiology, 64(6), 1996, pp. 975-983
The absorption and emission spectra, fluorescence quantum yields and l
ifetimes and triplet state properties of a boronated porphyrin, the te
trakiscarborane carboxylate ester of 2,4-(alpha,beta-dihydroxyethyl) d
euteroporphyrin IX (BOPP), have been determined, This compound is an a
lternative photodynamic therapy (PDT) agent that exhibits highly selec
tive tumor localization, with the potential to be used in conjunction
with boron neutron capture therapy, The photophysical characteristics
of BOPP are similar to other porphyrins and it exhibits marked aggrega
tion and acid-base speciation under typical physiological conditions,
In particular, protonation of the porphyrin imino (-N=) nitrogens occu
rs in the pH 5-7 region and influences the photophysical properties, T
ime-resolved confocal fluorescence imaging of the intracellular distri
bution of BOPP in C6 glioma cells indicates distinct subcellular local
ization and heterogeneity of emission. The results are interpreted and
discussed in terms of the possible mechanisms for cellular uptake and
localization.