title: In situ SAXRD study of sol-gel induced well-ordered mesoporous bioglasses for drug delivery.
abstract: In this work, two systems of mesoporous bioglasses (MBGs) were sol-gel derived using block copolymer pluronic F127 and P123, respectively, as templates. A two-dimensional hexagonal (P6mm) mesoporous structure was obtained for the two systems, with d-spacing in (100) reflection of 8.49 nm for P123-templated MBG (P123-MBG) and 10.26 nm for F127-templated MBG (F127-MBG). The phase transformation behavior for the systems was elucidated using an in situ synchrotron small angle X-ray diffraction approach, with the corresponding mechanisms proposed. It was indicated that both systems go through a complicated phase transformation, from a disordered to a finely ordered hexagonal structure during the self-evaporation process. The surfactants not only acted as templates for the ordered structure, but also enhanced the rigidity of Si-O network, which prevented disruption to the ordered Si-O arrangement by the Ca(2+) and P-O group. In vitro bioactivity study showed similar bioactivity for both the P123-MBG and F127-MBG systems. Drug loading and release studies using a model metoclopramide drug showed that both MBGs presented better loading and release compared to normal bioglass (BG). The significantly higher loading and better sustained release for P123-MBG, compared to F127-MBG, is attributed to its higher pore volume and surface area.
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue 50, Singapore 639798.
authors.forename: Y F
authors.initials: YF
authors.lastname: Zhao
authors.forename: S C J
authors.initials: SC
authors.lastname: Loo
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Chen
authors.forename: F Y C
authors.initials: FY
authors.lastname: Boey
authors.forename: J
authors.initials: J
authors.lastname: Ma
mesh_terms: D001031:Apatites / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D016503:Drug Delivery Systems; D005782:Gels / Q000737:chemistry*; D008787:Metoclopramide / Q000008:administration & dosage*; D046529:Microscopy, Electron, Transmission; D016062:Porosity; D053838:Scattering, Small Angle; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; C022107:Bioglass; D005782:Gels; D008787:Metoclopramide