In Situ Forming Poly(ethylene glycol)- Poly(L-lactide) Hydrogels via Michael Addition: Mechanical Properties, Degradation, and Protein Release

• Published in: Macromolecular chemistry and physics Vol. 213; no. 7; pp. 766 - 775
• Main Authors: Buwalda, Sytze J., Dijkstra, Pieter J., Feijen, Jan
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 13.04.2012; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; biodegradable; drug delivery systems; Exact sciences and technology; hydrogels; Organic polymers; PEG-PLLA; Physicochemistry of polymers; Properties and characterization; Solution and gel properties; star polymers; Biological properties; Ring opening polymerization; Viscoelasticity; drug delivery systems; biodegradable; End group; Biodegradability; Lactic acid copolymer; Drug carrier; Ethylene oxide polymer; Colloidal gel; Release; Lysozyme; PEG-PLLA; Michael addition; Swelling; Enzyme; Control release polymer; Albumin; Crosslinking; hydrogels; Ethylene oxide copolymer; Experimental study; In vitro; Glycosylases; Hydrolysis; star polymers; Optically active copolymer; Chemical modification; Glycosidases; Preparation; Hydrolases; Block copolymer; Aliphatic copolymer
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201100640

Chemically crosslinked hydrogels are prepared at remarkably low macromonomer concentrations from 8‐arm poly(ethylene glycol)‐poly(L‐lactide) star block copolymers bearing acrylate end groups (PEG‐(PLLAn)8‐AC, n = 4 or 12) and multifunctional PEG thiols (PEG‐(SH)n, n = 2, 4, or 8) through a Michael‐type addition reaction. Hydrogels are obtained within 1 min after mixing PEG‐(PLLA4)8 ‐AC and PEG‐(SH)8 in phosphate buffered saline, quickly reaching a high storage modulus of 17 kPa. Lysozyme and albumin are released for 4 weeks from PEG‐(PLLA12)8‐AC/PEG‐(SH)8 hydrogels. Lysozyme release from PEG‐(PLLA12)8‐AC/PEG‐(SH)2 and PEG‐(PLLA12)8‐AC/PEG‐(SH)4 hydrogels is significantly faster with complete release in 3 and 12 d, respectively, as a result of a combination of degradation and diffusion. Protein release from chemically crosslinkedhydrogels formed in situ by reaction between 8‐arm acrylated PEG‐PLLA star block copolymers and multifunctional PEG thiols is studied in relation to crosslink density and degradation properties. The hydrogels can be tuned with a broad range of mechanical, degradation, and release properties and therefore hold promise as a versatile drug delivery system.