Skip to main content
. Author manuscript; available in PMC: 2011 May 1.
Published in final edited form as: Biomaterials. 2010 Feb 6;31(13):3736–3743. doi: 10.1016/j.biomaterials.2010.01.058

Figure 4.

Figure 4

The immobilization efficiency and stability of acrylate-PEG-peptide macromers in PEGDA gels was assessed with a modified Lowry Assay for total protein concentration, as well as HUVEC seeding. (a) The Lowry assay, typically only used for large proteins, produced a linear standard curve from the short, soluble CGREDV peptide, even at low concentrations. (b) This standard curve was used to quantify the solution-based concentration of acrylate-PEG-CGRGDS and acrylate-PEG-CGRGES macromers, with a deviation from expected of 40–50%, with values comparable between both peptides. Bars indicate standard error. (c) gross appearance of hydrogel slabs after modified Lowry Assay in situ showing characteristic blue color with starting peptide concentration (μmol/mL). The linear dependence on concentration was also valid in solid hydrogels (inset, bars indicate standard deviation). (d) The assay tracked CGRGDS retention over time within hydrogels. A large percent of RGDS was lost on the first day during hydrogel equilibrium swelling. The remaining peptide was stable for at least 2 more days in the gel (n=3 for all samples), with up to 75% retention. Bars indicate standard deviation. (e) HUVEC morphology on PEGDA hydrogels with 4.0 μmol/mL PEG-CGRGES (top) or PEG-CGRGDS (bottom) 24 hours post-seeding. Scale Bars = 25 μm.