In situ forming poly(ethylene glycol)- Poly(L -lactide) hydrogels via michael addition: Mechanical properties, degradation, and protein release

摘要

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-(PLLA _n) _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-(PLLA _4) _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-(PLLA _(12)) _8-AC/PEG-(SH) _8 hydrogels. Lysozyme release from PEG-(PLLA _(12)) _8-AC/PEG-(SH) _2 and PEG-(PLLA _(12)) _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.