The Embedding of Meta-tetra(Hydroxyphenyl)-Chlorin into Silica Nanoparticle Platforms for Photodynamic Therapy and Their Singlet Oxygen Production and pH-dependent Optical Properties ¶

This study relates to nanoparticle (NP) platforms that attach to tumor cells externally and only deliver singlet oxygen for photodynamic therapy (PDT) while conserving the embedded photosensitizers (PS). As a model, we demonstrate the successful embedding of the PS meta-tetra(hydroxyphenyl)-chlorin ( m -THPC) in NP that are based on a sol–gel silica matrix and also show its positive effect on the singlet oxygen production. The embedding of m -THPC inside silica NP is accomplished by a modified StÖber sol–gel process, in which (3-aminopropyl)-triethoxysilane is introduced during the reaction. Singlet oxygen delivery by the targetable photodynamic NP exceeds that from free PS molecules. In the physiological pH range, there is no significant pH-induced decrease in the fluorescence of m -THPC embedded in silica NP, which might otherwise affect the efficiency of PDT.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74989/1/0031-8655_2003_0780587TEOMIS2.0.CO2.pd