title: Nanostructured hybrid hydrogels prepared by a combination of atom transfer radical polymerization and free radical polymerization.
abstract: A new method to prepare nanostructured hybrid hydrogels by incorporating well-defined poly(oligo (ethylene oxide) monomethyl ether methacrylate) (POEO(300)MA) nanogels of sizes 110-120 nm into a larger three-dimensional (3D) matrix was developed for drug delivery scaffolds for tissue engineering applications. Rhodamine B isothiocyanate-labeled dextran (RITC-Dx) or fluorescein isothiocyanate-labeled dextran (FITC-Dx)-loaded POEO(300)MA nanogels with pendant hydroxyl groups were prepared by activators generated electron transfer atom transfer radical polymerization (AGET ATRP) in cyclohexane inverse miniemulsion. Hydroxyl-containing nanogels were functionalized with methacrylated groups to generate photoreactive nanospheres. (1)H NMR spectroscopy confirmed that polymerizable nanogels were successfully incorporated covalently into 3D hyaluronic acid-glycidyl methacrylate (HAGM) hydrogels after free radical photopolymerization (FRP). The introduction of disulfide moieties into the polymerizable groups resulted in a controlled release of nanogels from cross-linked HAGM hydrogels under a reducing environment. The effect of gel hybridization on the macroscopic properties (swelling and mechanics) was studied. It is shown that swelling and nanogel content are independent of scaffold mechanics. In-vitro assays showed the nanostructured hybrid hydrogels were cytocompatible and the GRGDS (Gly-Arg-Gly-Asp-Ser) contained in the nanogel structure promoted cell-substrate interactions within 4 days of incubation. These nanostructured hydrogels have potential as an artificial extracellular matrix (ECM) impermeable to low molecular weight biomolecules and with controlled pharmaceutical release capability. Moreover, the nanogels can control drug or biomolecule delivery, while hyaluronic acid based-hydrogels can act as a macroscopic scaffold for tissue regeneration and regulator for nanogel release.
authors: Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors: Sidi A
authors: SA
authors: Bencherif
authors: Daniel J
authors: DJ
authors: Siegwart
authors: Abiraman
authors: A
authors: Srinivasan
authors: Ferenc
authors: F
authors: Horkay
authors: Jeffrey O
authors: JO
authors: Hollinger
authors: Newell R
authors: NR
authors: Washburn
authors: Krzysztof
authors: K
authors: Matyjaszewski
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry* / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019245:Compressive Strength; D055119:Elastic Modulus; D005109:Extracellular Matrix / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry* / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects; D049329:Nanostructures / Q000008:administration & dosage / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology; D016062:Porosity
chemical_list: D001672:Biocompatible Materials; D005609:Free Radicals; D020100:Hydrogels; D011108:Polymers