title: Time Dependence of Material Properties of Polyethylene Glycol Hydrogels Chain Extended with Short Hydroxy Acid Segments.
abstract: The objective of this work was to investigate the effect of chemical composition and segment number (n) on gelation, stiffness, and degradation of hydroxy acid-chain-extended star polyethylene glycol acrylate (SPEXA) gels. The hydroxy acids included glycolide (G,), L-lactide (L), p-dioxanone (D) and -caprolactone (C). Chain-extension generated water soluble macromers with faster gelation rates, lower sol fractions, higher compressive moduli, and a wide-ranging degradation times when crosslinked into a hydrogel. SPEGA gels with the highest fraction of inter-molecular crosslinks had the most increase in compressive modulus with n whereas SPELA and SPECA had the lowest increase in modulus. SPEXA gels exhibited a wide range of degradation times from a few days for SPEGA to a few weeks for SPELA, a few months for SPEDA, and many months for SPECA. Marrow stromal cells and endothelial progenitor cells had the highest expression of vasculogenic markers when co-encapsulated in the faster degrading SPELA gel.
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Danial
authors.initials: D
authors.lastname: Barati
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Seyedsina
authors.initials: S
authors.lastname: Moeinzadeh
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Ozan
authors.initials: O
authors.lastname: Karaman
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Esmaiel
authors.initials: E
authors.lastname: Jabbari
keywords: cell encapsulation; hydrogel chain extension; hydroxy acids