title: Photopolymerized thermosensitive poly(HPMAlactate)-PEG-based hydrogels: effect of network design on mechanical properties, degradation, and release behavior.
abstract: Photopolymerized thermosensitive A-B-A triblock copolymer hydrogels composed of poly(N-(2-hydroxypropyl)methacrylamide lactate) A-blocks, partly derivatized with methacrylate groups to different extents (10, 20, and 30%) and hydrophilic poly(ethylene glycol) B-blocks of different molecular weights (4, 10, and 20 kDa) were synthesized. The aim of the present study was to correlate the polymer architecture with the hydrogel properties, particularly rheological, swelling, degradation properties and release behavior. It was found that an increasing methacrylation extent and a decreasing PEG molecular weight resulted in increasing gel strength and cross-link density, which tailored the degradation profiles from 25 to more than 300 days. Polymers having small PEG blocks showed a remarkable phase separation into polymer- and water-rich domains, as demonstrated by confocal microscopy. Depending on the hydrophobic domain density, the loaded protein resides in the hydrophilic pores or is partitioned into hydrophilic and hydrophobic domains, and its release from these compartments is tailored by the extent of methacrylation and by PEG length, respectively. As the mechanical properties, degradation, and release profiles can be fully controlled by polymer design and concentration, these hydrogels are suitable for controlled protein release.
authors.affiliation: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
authors.forename: Roberta
authors.initials: R
authors.lastname: Censi
authors.forename: Tina
authors.initials: T
authors.lastname: Vermonden
authors.forename: Hendrik
authors.initials: H
authors.lastname: Deschout
authors.forename: Kevin
authors.initials: K
authors.lastname: Braeckmans
authors.forename: Piera
authors.initials: P
authors.lastname: di Martino
authors.forename: Stefaan C
authors.initials: SC
authors.lastname: De Smedt
authors.forename: Cornelus F
authors.initials: CF
authors.lastname: van Nostrum
authors.forename: Wim E
authors.initials: WE
authors.lastname: Hennink
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D016503:Drug Delivery Systems; D020100:Hydrogels; D009682:Magnetic Resonance Spectroscopy; D018613:Microscopy, Confocal; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry*; D012212:Rheology; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D000178:Acrylamides; D020100:Hydrogels; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; C032976:N-(2-hydroxypropyl)methacrylamide