Browsing by Subject "Photodynamic action"

Now showing 1 - 3 of 3

Open Access
Near-IR absorbing BODIPY derivatives as glutathione-activated photosensitizers for selective photodynamic action
(Wiley-VCH Verlag, 2014) Turan, I. S.; Cakmak, F. P.; Yildirim, D. C.; Cetin Atalay, R.; Akkaya, E. U.
Enhanced spatiotemporal selectivity in photonic sensitization of dissolved molecular oxygen is an important target for improving the potential and the practical applications of photodynamic therapy. Considering the high intracellular glutathione concentrations within cancer cells, a series of BODIPY-based sensitizers that can generate cytotoxic singlet oxygen only after glutathione-mediated cleavage of the electron-sink module were designed and synthesized. Cell culture studies not only validate our design, but also suggest an additional role for the relatively hydrophobic quencher module in the internalization of the photosensitizer.
Open Access
Remote-controlled release of singlet oxygen by the plasmonic heating of endoperoxide-modified gold nanorods: towards a paradigm change in photodynamic therapy
(Wiley-VCH Verlag, 2016) Kolemen, S.; Ozdemir, T.; Lee, D.; Kim, G. M.; Karatas, T.; Yoon, J.; Akkaya, E. U.
The photodynamic therapy of cancer is contingent upon the sustained generation of singlet oxygen in the tumor region. However, tumors of the most metastatic cancer types develop a region of severe hypoxia, which puts them beyond the reach of most therapeutic protocols. More troublesome, photodynamic action generates acute hypoxia as the process itself diminishes cellular oxygen reserves, which makes it a self-limiting method. Herein, we describe a new concept that could eventually lead to a change in the 100 year old paradigm of photodynamic therapy and potentially offer solutions to some of the lingering problems. When gold nanorods with tethered endoperoxides are irradiated at 808 nm, the endoperoxides undergo thermal cycloreversion, resulting in the generation of singlet oxygen. We demonstrate that the amount of singlet oxygen produced in this way is sufficient for triggering apoptosis in cell cultures. EPT sees the light: When gold nanorods with tethered endoperoxides are irradiated with near-infrared light, the endoperoxides undergo thermal cycloreversion, resulting in the generation of singlet oxygen. The amount of singlet oxygen generated by these nanocomposites is sufficient for triggering apoptosis in cell cultures.
Open Access
Thinking outside the silicon box: molecular and logic as an additional layer of selectivity in singlet oxygen generation for photodynamic therapy
(2009) Ozlem, S.; Akkaya, E. U.
A simple derivative of a well-known dye bodipy appears to be a satisfactory sensitizer for singlet oxygen. Moreover, the rate of singlet oxygen generation can be modulated by two cancer-related cellular parameters, sodium ion concentration and acidity. Singlet oxygen generation rate is maximal when sodium ions and an organic acid were added. The operation of this molecular automaton follows AND logic, which introduces an additional layer of selectivity in the photodynamic action of the reagent. It should also be noted that in this system sensing, computing and actuating functions are realized within a single molecule. Copyright © 2008 American Chemical Society.