title: In vitro characterization of vascular endothelial growth factor and dexamethasone releasing hydrogels for implantable probe coatings.
abstract: Anti-fouling hydrogel coatings, copolymers of 2-hydroxyethyl methacrylate, 1-vinyl-2-pyrrolidinone, and polyethylene glycol, were investigated for the purpose of improving biosensor biocompatibility. These coatings were modified to incorporate poly(lactide-co-glycolide) (PLGA) microspheres in order to release dexamethasone (DX) and/or vascular endothelial growth factor (VEGF). DX and VEGF release kinetics from microspheres, hydrogels, and microspheres embedded in hydrogels were determined in 2-week and 1-month studies. Overall, monolithic, non-degradable hydrogel drug release had an initial burst followed by release at a significantly lower amount. Microsphere drug release kinetics exhibited an initial burst followed by sustained release for 1 month. Embedding microspheres in hydrogels resulted in attenuated drug delivery. VEGF release from embedded microspheres, 1.1+/-0.3 ng, was negligible compared to release from hydrogels, 197+/-33 ng. After the initial burst from DX-loaded hydrogels, DX release from embedded microspheres was similar to that of hydrogels. The total DX release from hydrogels, 155+/-35 microg, was greater than that of embedded microspheres, 60+/-6 microg. From this study, hydrogel sensor coatings should be prepared incorporating VEGF in the hydrogel and DX either in the hydrogel or in DX microspheres embedded in the hydrogel.
authors.affiliation: Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC 27708, USA.
authors.forename: L W
authors.initials: LW
authors.lastname: Norton
authors.forename: E
authors.initials: E
authors.lastname: Tegnell
authors.forename: S S
authors.initials: SS
authors.lastname: Toporek
authors.forename: W M
authors.initials: WM
authors.lastname: Reichert
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003907:Dexamethasone / Q000737:chemistry*; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004797:Enzyme-Linked Immunosorbent Assay; D005938:Glucocorticoids / Q000737:chemistry*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020100:Hydrogels / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D007700:Kinetics; D019344:Lactic Acid / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008863:Microspheres; D008956:Models, Chemical; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D012235:Rhodamines / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D004337:Drug Carriers; D005938:Glucocorticoids; D020100:Hydrogels; D011108:Polymers; D012235:Rhodamines; D042461:Vascular Endothelial Growth Factor A; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011100:Polyglycolic Acid; D019344:Lactic Acid; D003907:Dexamethasone