A pH-Responsive, TiO(2)-Attached Porphyrin for Singlet Oxygen Production in Aqueous Solution.
Posted on March 10th, 2010 | by Stem Cell News || Related Articles |
A pH-Responsive, TiO(2)-Attached Porphyrin for Singlet Oxygen Production in Aqueous Solution.
ACS Appl Mater Interfaces. 2009 Aug 26;1(8):1778-1784
Authors: Li W, Gandra N, Ellis ED, Courtney S, Li S, Butler E, Gao R
A pH-responsive, TiO(2)-attached sensitizer was prepared based on the adsorption of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) onto TiO(2) nanoparticles. This colloidally dispersed TiO(2)-attached TCPP behaves as a single-phase colloidal sensitizer at pH 1.0-3.3 with quantum yields of singlet oxygen production (Phi(Delta)) between 0.20 and 0.25, as a heterogeneous particle sensitizer at pH 3.5-6.0 with Phi(Delta) between 0.25 and 0.50, and as homogeneous free TCPP molecules in alkaline solutions with Phi(Delta) = 0.53. The changes in Phi(Delta) are fully consistent with pH dependent adsorption of TCPP on TiO(2) surface. Recovery yields of 99.8% for TCPP and 98.8% for TiO(2) were obtained from 1.4 mM TiO(2)-attached TCPP. We attribute its photosensitization ability to retain TCPP solubility on TiO(2) surface and hence activity. This novel system shows a potential to bridge the gap between easily recoverable and highly efficient sensitizers.
PMID: 20209036 [PubMed - as supplied by publisher]