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. Author manuscript; available in PMC: 2008 May 21.
Published in final edited form as: Prog Polym Sci. 2008 Feb;33(2):167–179. doi: 10.1016/j.progpolymsci.2007.09.006

Fig. 2.

Fig. 2

(A) Materials were created from the reaction of poly(ethylene glycol)-b-poly(lactic acid)-diacrylate (PEG-PLA-DA) and pentaerythritol tetrakis(3-mercaptopropionate) (tetrathiol); (B) Conversion profiles of initiatorless photopolymerizations: (a) 100% PEG-PLA-diacrylate, light intensity = 5 mW/cm2, (b) 85 mol% PEG-PLA-diacrylate, 15 mol% tetrathiol, light intensity = 5 mW/cm2, (c) 85 mol% PEG-PLA-diacrylate, 15 mol% tetrathiol, light intensity = 50 mW/cm2; (C) Experimental mass loss profiles for degradable thiol-acrylate networks made from a PEG-PLA-DA and 10 (□), 30 (○), and 50 (△ ) mol% tetrathiol. (D) Pictorial representation of the initial monomer molecules, crosslinked polymer networks, and degradation products for materials formed from (a) chain-growth polymerization mechanism and (b) mixed-mode mechanism 25. (E) Encapsultion of human mesenchymal stem cells in PEG-peptide gels synthesized through the thiol-acrylate chemistry. Micrographs are from day 7 of culture of hMSCs encapsulated at a density of 5×106 cells/ml in gels formed from (a) PEG-DA and (b) PEG-DA with 5mM CRGDSG. The images are stained with LIVE/DEAD to differentiate living cells (gray) from dead (black), and illustrate the ability of the CRGDSG functionalized gels to promote hMSC survival. Scale bar=50μm.