27 October 2014 Anticancer phototherapy using activation of E-combretastatins by two-photon–induced isomerization
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The photoisomerization of relatively nontoxic E-combretastatins to clinically active Z-isomers is shown to occur in solution through both one- and two-photon excitations at 340 and 625 nm, respectively. The photoisomerization is also demonstrated to induce mammalian cell death by a two-photon absorption process at 625 nm. Unlike conventional photodynamic therapy (PDT), the mechanism of photoisomerization is oxygen-independent and active in hypoxic environments such as in tumors. The use of red or near-infrared (NIR) light for two-photon excitation allows greater tissue penetration than conventional UV one-photon excitation. The results provide a baseline for the development of a novel phototherapy that overcomes nondiscriminative systemic toxicity of Z-combretastatins and the limitations of PDT drugs that require the presence of oxygen to promote their activity, with the added benefits of two-photon red or NIR excitation for deeper tissue penetration.
© 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)
Kathrin M. Scherer, Roger H. Bisby, Stanley W. Botchway, John A. Hadfield, Anthony W. Parker, "Anticancer phototherapy using activation of E-combretastatins by two-photon–induced isomerization," Journal of Biomedical Optics 20(5), 051004 (27 October 2014). https://doi.org/10.1117/1.JBO.20.5.051004 . Submission:

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