title: Synthesis and characterization of degradable p(HEMA) microgels: use of acid-labile crosslinkers.
abstract: New divinyl-functionalized acetal-based crosslinkers were synthesized as building elements to form acid-labile microgel particles for controlled-release applications. The synthesized crosslinkers underwent hydrolysis at slightly acidic pHs in less than 1 h while they were stable at neutral pHs for longer times. HEMA was copolymerized with the crosslinkers via an inverse emulsion polymerization technique using a redox initiator system at room temperature to form crosslinked, colloidal p(HEMA) microgels. Microgels in diameters ranging from 150 to 475 nm with narrow distribution could be produced. The crosslinking density and the diameter of the microgels were found to be controlled by monomer/crosslinker feed ratio. The microgels demonstrated a pH-dependent cleavage behavior that mimicked the pH-dependent hydrolysis profile of the acid-labile crosslinkers. Model biomacromolecules, i.e., Rhodamine B-labeled dextran and BSA were efficiently loaded into the microgels. The release of the biomolecules from p(HEMA) microgels was also found to be controllable by the pH of the environment similar to the particle degradation. The protein released from the microgels was observed to retain its structural stability.
authors: Centre for Advanced Macromolecular Design, School of Chemical Sciences and Engineering, The University of New South Wales, Kensington, Sydney, NSW 2052 Australia. vbulmus@unsw.edu.au
authors: Volga
authors: V
authors: Bulmus
authors: Yannie
authors: Y
authors: Chan
authors: Quyen
authors: Q
authors: Nguyen
authors: Hong L
authors: HL
authors: Tran
mesh_terms: D003102:Colloids / Q000138:chemical synthesis* / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000138:chemical synthesis / Q000737:chemistry; D004337:Drug Carriers / Q000138:chemical synthesis* / Q000737:chemistry; D005782:Gels / Q000138:chemical synthesis / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D010316:Particle Size; D011102:Polyhydroxyethyl Methacrylate / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D003102:Colloids; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D008689:Methacrylates; D011102:Polyhydroxyethyl Methacrylate; C005044:hydroxyethyl methacrylate