Temperature effects on photosensitized processes.
The singlet-oxygen-mediated reaction of meso-tetraphenylporphine tetrasulphonate (TPPS4) with different chemical acceptors in buffered aqueous solution was studied as a function of temperature. Imidazole, tryptophan, dimethyl p-nitrosoaniline, (RNO) and furfuryl alcohol served as acceptors. The measurements were performed in real time by spectroscopic or electrochemical monitoring of the consumption of the various reagents, acceptors or dissolved oxygen as a function of the absorbed energy. The results show the following increases in the reaction rate over the temperature range 15-45 degrees C: tryptophan (86%), RNO (90%), furfuryl alcohol (150%) and imidazole (210%). The influence of temperature-correlated changes in the initial oxygen concentration and pH was investigated. Possible implications of the present results for the synergistic influence of hyperthermia and photodynamic therapy are discussed.
Gottfried
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V
Department of Chemistry, Technion-Israel Institute of Technology, Haifa.
Kimel
S
S
D007202:Indicators and Reagents; D007700:Kinetics; D008027:Light; D011166:Porphyrins / Q000737:chemistry*; D011838:Radiation-Sensitizing Agents / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods; D013816:Thermodynamics
D007202:Indicators and Reagents; D011166:Porphyrins; D011838:Radiation-Sensitizing Agents; D012996:Solutions; C016136:tetraphenylporphine sulfonate