title: Functional hydrophobin-coating of thermally hydrocarbonized porous silicon microparticles.
abstract: Porous silicon (PSi) particles have been widely used in modulating the dissolution rate of various types of drugs loaded within its mesopores. This material can be surface treated in order to vary its hydrophobicity and several other properties, such as drug loading degree and release rate. Hydrophobins are a family of self-assembling proteins of fungal origin which have the ability to form layers on hydrophobic materials. This type of protein layer can modify the characteristics and control the binding properties of the surface on which it assembles. In this study, we have developed a procedure to coat thermally hydrocarbonized-PSi microparticles with hydrophobin II (HFBII) in order to modify the particles' hydrophobicity and to improve their biocompatibility, while maintaining intact the advantageous drug releasing properties of the PSi. The HFBII content adsorbed onto the particles was successfully quantified by a protein assay. Drug dissolution and permeation across Caco-2 cell monolayers were also conducted, together with viability studies in AGS, Caco-2 and HT-29 cells. The characterization and coating stability assessment showed that the HFBII-coating desorbs partially from the particles' surface as the pH increases. The HFBII coating also improved the biocompatibility of the particles without compromising the enhanced drug permeation or release.
authors.affiliation: Division of Pharmaceutical Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland. luis.bimbo@helsinki.fi
authors.forename: Luis M
authors.initials: LM
authors.lastname: Bimbo
authors.forename: Ermei
authors.initials: E
authors.lastname: Mäkilä
authors.forename: Janne
authors.initials: J
authors.lastname: Raula
authors.forename: Timo
authors.initials: T
authors.lastname: Laaksonen
authors.forename: Päivi
authors.initials: P
authors.lastname: Laaksonen
authors.forename: Katharina
authors.initials: K
authors.lastname: Strommer
authors.forename: Esko I
authors.initials: EI
authors.lastname: Kauppinen
authors.forename: Jarno
authors.initials: J
authors.lastname: Salonen
authors.forename: Markus B
authors.initials: MB
authors.lastname: Linder
authors.forename: Jouni
authors.initials: J
authors.lastname: Hirvonen
authors.forename: Hélder A
authors.initials: HA
authors.lastname: Santos
mesh_terms: D018938:Caco-2 Cells; D002470:Cell Survival; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008863:Microspheres; D010539:Permeability; D004364:Pharmaceutical Preparations / Q000008:administration & dosage; D016062:Porosity; D012825:Silicon / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties; D013696:Temperature; D014242:Trichoderma / Q000737:chemistry* / Q000378:metabolism
chemical_list: D020099:Coated Materials, Biocompatible; D004337:Drug Carriers; D005656:Fungal Proteins; D004364:Pharmaceutical Preparations; D012825:Silicon