title: pH and redox-operated nanovalve for size-selective cargo delivery on hollow mesoporous silica spheres.
abstract: A pH and redox dual-responsive nanovalve with a long stalk was introduced on the surface of hollow mesoporous silica nanoparticles (HMSs-S1) to achieve cargo size selectivity delivery. The responsive nanovalve was designed by constructing of a stalk/β-cyclodextrins (CDs) supramolecular complex, which is based on an acid-labile acetal group and the host-guest interactions between β-cyclodextrins and ferrocenyl moiety (Fc). With stimulation by different pH and H2O2, Rhodamine 6G showed well-responsive behavior. On account of the long stalks of nanovalve, doxorubicin hydrochloride and 5-fluorouracil with different sized cargos are encapsulated in HMSs-S1 to test its behavior of cargo size-selective delivery. Moreover the HMSs-S2 with a short stalk based on β-CDs/Fc inclusion complex is synthesized to load small sized 5-FU drug as contrast experiment. Compared with HMSs-S2, HMSs-S1 is compatible with larger drug molecules such as Rhodamine 6G (R6G) and doxorubicin hydrochloride (DOX), while small sized 5-fluorouracil (5-FU) is unable to be sealed by the nanovalve. Dual responsiveness and drug size selectivity make mechanized HMSs possess potential applications in drug delivery system.
authors.affiliation: College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Xinyun
authors.initials: X
authors.lastname: Zhu
authors.affiliation: College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China. Electronic address: wang-caiqi@ucas.ac.cn.
authors.forename: Cai-Qi
authors.initials: CQ
authors.lastname: Wang
mesh_terms: D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D012822:Silicon Dioxide
keywords: Cargo size-selective; Drug delivery system; Dual-responsive; Hollow mesoporous silica spheres; Supramolecular nanovalve