CHED 1569 |
| Despite the promising results of photodynamic therapy (PDT) to date, the selectivity of PDT leaves much to be desired as it often gives rise to clinical side effects such as prolonged light sensitivity. We propose a new approach to achieve both PDT selectivity and improved solubility in aqueous solutions by controlling the production and quenching rates of singlet oxygen, which can be accomplished with pH dependent meso-tetra(4-carboxyphenyl)porphine (TCPP)-titania nanocomposites. The formation of singlet oxygen was measured by its luminescence emission at 1270 nm. The adsorption of TCPP on titania surface is pH dependent. Large quenching rate and strong adsorption between singlet oxygen and titania nanoparticles at higher pH suppress the production and reactivity of singlet oxygen. The release of singlet oxygen can be resumed by decreasing pH down to a certain point (~ 6 for our system), where singlet oxygen quenching by titania is not observed because of the strong binding of TCPP on titania surface. |
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Research and Education in Material Science
8:00 AM-11:25 AM, Thursday, April 10, 2008 Hilton New Orleans Riverside -- HEC B, Oral
Division of Chemical Education |