title: Tailoring the degradation kinetics of mesoporous silicon structures through PEGylation.
abstract: Injectable and implantable porosified silicon (pSi) carriers and devices for prolonged and controlled delivery of biotherapeutics offer great promise for treatment of various chronic ailments and acute conditions. Polyethylene glycols (PEGs) are important surface modifiers currently used in clinic mostly to avoid uptake of particulates by reticulo-endothelial system (RES). In this work we show for the first time that covalent attachment of PEGs to the pSi surface can be used as a means to tune degradation kinetics of silicon structures. Seven PEGs with varying molecular weights (245, 333, 509, 686, 1214, 3400, and 5000 Da) were employed and the degradation of PEGylated pSi hemispherical microparticles in simulated physiological conditions was monitored by means of ICP-AES, SEM, and fluorimetry. Biocompatibility of the systems with human macrophages in vitro was also evaluated. The results clearly indicate that controlled PEGylation of silicon microparticles can offer a sensitive tool to finely tune their degradation kinetics and that the systems do not induce release of proinflammatory cytokines IL-6 and IL-8 in THP1 human macrophages.
authors.affiliation: Department of Nanomedicine and Biomedical Engineering, School of Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA. Biana.Godin-Vilentchouk@uth.tmc.edu
authors.forename: Biana
authors.initials: B
authors.lastname: Godin
authors.forename: Jianhua
authors.initials: J
authors.lastname: Gu
authors.forename: Rita E
authors.initials: RE
authors.lastname: Serda
authors.forename: Rohan
authors.initials: R
authors.lastname: Bhavane
authors.forename: Ennio
authors.initials: E
authors.lastname: Tasciotti
authors.forename: Ciro
authors.initials: C
authors.lastname: Chiappini
authors.forename: Xuewu
authors.initials: X
authors.lastname: Liu
authors.forename: Takemi
authors.initials: T
authors.lastname: Tanaka
authors.forename: Paolo
authors.initials: P
authors.lastname: Decuzzi
authors.forename: Mauro
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D002460:Cell Line; D005453:Fluorescence; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D016209:Interleukin-8 / Q000378:metabolism; D007700:Kinetics; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D016062:Porosity / Q000187:drug effects; D012825:Silicon / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D016209:Interleukin-8; D011092:Polyethylene Glycols; D012825:Silicon