title: Adsorption of lysozyme on hyaluronic acid functionalized SBA-15 mesoporous silica: a possible bioadhesive depot system.
abstract: Silica-based ordered mesoporous materials are very attractive matrices to prepare smart depot systems for several kinds of therapeutic agents. This work focuses on the well-known SBA-15 mesoporous silica and lysozyme, an antimicrobial protein. In order to improve the bioadhesion properties of SBA-15 particles, the effect of hyaluronic acid (HA) functionalization on lysozyme adsorption was investigated. SBA-15 samples having high (H-SBA) and low (L-SBA) levels of functionalization were analyzed during the three steps of the preparations: (1) introduction of the -NH2 groups to obtain the SBA-NH2 samples; (2) functionalization with HA to obtain the SBA-HA matrices; (3) adsorption of lysozyme. All silica matrices were characterized through N2-adsorption/desorption isotherms, small-angle X-ray scattering, transmission electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The whole of the experimental data suggests that a high level of functionalization of the silica surface allows for a negligible lysozyme adsorption mainly due to unfavorable electrostatic interactions (H-SBA-NH2) or steric hindrance (H-SBA-HA). A low degree of functionalization of the silica surface brings about a very good performance toward lysozyme adsorption, being 71% (L-SBA-NH2) and 63% (L-SBA-HA) respectively, compared to that observed for original SBA-15. Finally, two different kinetic models--a "pseudo-second order" and a "intraparticle diffusion"--were compared to fit lysozyme adsorption data, the latter being more reliable than the former.
authors.affiliation: Department of Chemical and Geological Sciences, University of Cagliari-CSGI and CNBS, Cittadella Universitaria , S.S. 554 bivio Sestu, 09042- Monserrato (Cagliari), Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Medda
authors.forename: Maria F
authors.initials: MF
authors.lastname: Casula
authors.forename: Maura
authors.initials: M
authors.lastname: Monduzzi
authors.forename: Andrea
authors.initials: A
authors.lastname: Salis
mesh_terms: D000268:Adhesiveness; D000327:Adsorption; D000818:Animals; D006820:Hyaluronic Acid / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D016062:Porosity; D011487:Protein Conformation; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: C509969:SBA-15; D012821:Silanes; D012822:Silicon Dioxide; D006820:Hyaluronic Acid; D009113:Muramidase; D009584:Nitrogen