Additional approach to PDT: type III mechanism and the role of native free radicals

Dezso Gal; Tamas Kriska; Tatiana G. Shutova; Andras Nemeth

doi:10.1117/12.424450

9 April 2001 Additional approach to PDT: type III mechanism and the role of native free radicals

Dezso Gal, Tamas Kriska, Tatiana G. Shutova, Andras Nemeth

Proceedings Volume 4248, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy X; (2001) https://doi.org/10.1117/12.424450
Event: BiOS 2001 The International Symposium on Biomedical Optics, 2001, San Jose, CA, United States

Abstract

It has been suggested by us earlier that interactions of excited triplet sensitizer (3PS) and native free radicals compete with Type I (sensitizer radical mediated) and Type II (singlet oxygen mediated) mechanisms during PDT. Evidence such as fall in the overall radical concentration in vivo ( in mice tumors) during PDT and in the life time of 3PS caused by free radicals supported this assumption In addition, following results have been obtained recently. 1.) Excited Photofrin II and m-THPC affected luminol dependent chemiluminescence (CL) generated by respiratory burst of macrophages like free radical inhibitors. 2.) Quantification of spin trapping for chemical and in vitro systems by kinetic ESR spectrometry yielded detailed knowledge of triplet-doublet interactions 3.)Measurements in open systems (tank reactor) yielded data for the interactions between 3PS and peroxy type radicals 4.)Simulation of experimental data based on mechanisms suggested gave fair agreement. Based on experimental results new PS-s called Antioxidant Carrier Sensiters (ACS-s) have been devised, synthesized and tested one of them showing enhanced activity for PDT.

Citation Download Citation

Dezso Gal, Tamas Kriska, Tatiana G. Shutova, and Andras Nemeth "Additional approach to PDT: type III mechanism and the role of native free radicals", Proc. SPIE 4248, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy X, (9 April 2001); https://doi.org/10.1117/12.424450

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