title: pH-responsive silica nanoparticles for controllable 1O2 generation.
abstract: pH-responsive (1)O(2) photosensitizing systems may serve as selective photodynamic therapy (PDT) agents by targeting the acidic interstitial fluid of many kinds of tumors. In this work, we present a pH-responsive nanoparticle-based platform for controllable (1)O(2) generation, in which a hydrophobic (1)O(2) photosensitizer (meso-tetraphenylporphyrin, TPP) and a pH indicator (Bromocresol Purple, BCP, or Bromothymol Blue, BTB) are simultaneously encapsulated in organically modified silica nanoparticles (OSNP). In basic conditions, the pH indicator absorbs light competitively and thus restricts sensitizer excitation. In acidic solution, the blue shifted absorption of the pH indicator allows the efficient excitation of the sensitizer. The pH indicator serves as an 'inner filter' to modulate effectively the excitation of the sensitizer and thus the (1)O(2) generation efficiency.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors.forename: Zhaobo
authors.initials: Z
authors.lastname: Li
authors.forename: Jianguang
authors.initials: J
authors.lastname: Wang
authors.forename: Jingrong
authors.initials: J
authors.lastname: Chen
authors.forename: Wanhua
authors.initials: W
authors.lastname: Lei
authors.forename: Xuesong
authors.initials: X
authors.lastname: Wang
authors.forename: Baowen
authors.initials: B
authors.lastname: Zhang
mesh_terms: D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010100:Oxygen / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; C409084:tetraphenylporphyrin; D012822:Silicon Dioxide; D010100:Oxygen