title: Bilayered (silica-chitosan) coatings for studying dye release in aqueous media: The role of chitosan properties.
abstract: Chitosan and bilayered--Rhodamine 6G impregnated silica-chitosan--coatings (300-3000 nm thick) were prepared and investigated as a model for controlled drug release. Properties of native, ionically (sodium triphosphate) and covalently (glutaraldehyde) cross-linked layers of chitosan in contact with aqueous phase (modeling human blood pH of ca. 7.3) were investigated. The cross-linking was confirmed by attenuated total reflection (ATR) Fourier transform infrared (FTIR), energy-dispersive spectroscopy (EDS) and solid state (13)C nuclear magnetic resonance (NMR) spectroscopy. The evolution of advancing water contact angles as a function of time was measured, and from the results restricted mobility of polymer segments in the interfacial layer of cross-linked chitosan coatings were assumed. Spectroscopic ellipsometry measurements showed that covalent cross-linking leads to a lowered, while ionic cross-linking to an increased swelling degree of chitosan layers. Despite the swelling behavior both cross-linked chitosan layers showed significant retard effect on dye release from the bilayered coatings.
authors.affiliation: Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, H-1521 Budapest, Hungary.
authors.forename: Mátyás
authors.initials: M
authors.lastname: Dabóczi
authors.affiliation: Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, H-1521 Budapest, Hungary.
authors.forename: Emőke
authors.initials: E
authors.lastname: Albert
authors.affiliation: Research Institute for Technical Physics and Material Science, Centre for Energy Research, Hungarian Academy of Sciences, H-1121 Budapest, Hungary.
authors.forename: Emil
authors.initials: E
authors.lastname: Agócs
authors.affiliation: Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, H-1521 Budapest, Hungary.
authors.forename: Márta
authors.initials: M
authors.lastname: Kabai-Faix
authors.affiliation: Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, H-1521 Budapest, Hungary. Electronic address: zhorvolgyi@mail.bme.hu.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Hórvölgyi
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010539:Permeability; D016062:Porosity; D012235:Rhodamines / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D012235:Rhodamines; C026188:rhodamine 6G; D014867:Water; D012822:Silicon Dioxide; D048271:Chitosan
keywords: Bilayered coatings; Contact angle; Cross-linked chitosan; Dye release; Ellipsometry; Swelling