title: A new approach for the one-step synthesis of bioactive PS vs. PMMA silica hybrid microspheres as potential drug delivery systems.
abstract: In this work, hybrid microspheres were prepared in a two-step process combining the emulsifier free-emulsion polymerization and the sol-gel coating method. In the first step, polystyrene (St) and poly(methyl methacrylate) (PMMA) microspheres were prepared as sacrificial template and in the second step a silanol shell was fabricated. The functionalized surface of the hybrid microspheres by silane analogs (APTES, TEOS) resulted in enhanced effects. The hollow microspheres were resulted either in an additional step by template dissolution and/or during the coating process. The microspheres' surface interactions and the size distribution were optimized by treatment in simulated body fluids, which resulted in the in vitro prediction of bioactivity. The bioassay test indicated that the induced hydroxyapatite resembled in structure to naturally occurring bone apatite. The drug doxorubicin (DOX) was used as a model entity for the evaluation of drug loading and release. The drug release study was performed in two different pH conditions, at acidic (pH=4.5) close to cancer cell environment and at slightly basic pH (pH=7.4) resembling the orthopedic environment. The results of the present study indicated promising hybrid microspheres for the potential application as drug delivery vehicles, for dual orthopedic functionalities in bone defects, bone inflammation, bone cancer and bone repair.
authors.affiliation: Laboratory for Sol-Gel, Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR "Demokritos", 153 10 Ag. Paraskevi Attikis, Greece; Department of Materials Science, School of Natural Sciences, University of Patras, 26 500 Patras, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Angelopoulou
authors.affiliation: Laboratory for Sol-Gel, Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR "Demokritos", 153 10 Ag. Paraskevi Attikis, Greece. Electronic address: elefth@chem.ims.demokritos.gr.
authors.forename: E K
authors.initials: EK
authors.lastname: Efthimiadou
authors.affiliation: Laboratory for Sol-Gel, Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR "Demokritos", 153 10 Ag. Paraskevi Attikis, Greece.
authors.forename: N
authors.initials: N
authors.lastname: Boukos
authors.affiliation: Laboratory for Sol-Gel, Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR "Demokritos", 153 10 Ag. Paraskevi Attikis, Greece.
authors.forename: G
authors.initials: G
authors.lastname: Kordas
mesh_terms: D004317:Doxorubicin / Q000494:pharmacology; D016503:Drug Delivery Systems / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D019904:Polymethyl Methacrylate / Q000138:chemical synthesis*; D011137:Polystyrenes / Q000138:chemical synthesis*; D012822:Silicon Dioxide / Q000138:chemical synthesis*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D011137:Polystyrenes; D012822:Silicon Dioxide; D004317:Doxorubicin; D019904:Polymethyl Methacrylate
keywords: Bioactivity; Drug release; Hollow silica microspheres; Hybrid microspheres; Hydroxyapatite