title: Comparative study of LbL and crosslinked pH sensitive PEGylated LbL microspheres: synthesis, characterization and biological evaluation.
abstract: In this report, the fabrication of hollow, pH-sensitive microspheres using the layer by layer method is being demonstrated. The process is based on the coating of colloidal silica templates with polyelectrolyte layers, followed by dissolution of the core using a buffer system of hydrofluoric acid and ammonium fluoride. With this buffer system, the template can be dissolved in mild pH conditions, where the polymeric layers are still stable. The resulting microspheres show pH dependent properties, where they swell and dissolve at a certain pH value. In order to improve the nanocontainers properties, such as solubility and cytotoxicity a second specimen of microspheres was fabricated by coating the fabricated microspheres with one layer of poly(acrylic acid) and one layer of methoxy-polyethylene glycol amine, and then these additional layers were crosslinked by carbodiimide chemistry. Loading and release properties of the fabricated microspheres have been studied in order to investigate their behavior as a function of pH and ionic strength. These novel microspheres have potential application in the fields of drug delivery, diagnostics and life sciences.
authors.affiliation: Sol-Gel Laboratory, Institute for Advanced Materials, Physicochemical Processes, Nanotechnology & Microsystems, NCSR Demokritos, 153 10 Aghia Paraskevi Attikis, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Kainourgios
authors.forename: E K
authors.initials: EK
authors.lastname: Efthimiadou
authors.forename: L-A
authors.initials: LA
authors.lastname: Tziveleka
authors.forename: G S
authors.initials: GS
authors.lastname: Pappas
authors.forename: N
authors.initials: N
authors.lastname: Boukos
authors.forename: G
authors.initials: G
authors.lastname: Kordas
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D003432:Cross-Linking Reagents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D006863:Hydrogen-Ion Concentration; D061986:MCF-7 Cells; D008863:Microspheres; D010316:Particle Size; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D012995:Solubility; D013329:Structure-Activity Relationship; D013499:Surface Properties; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D011092:Polyethylene Glycols