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. Author manuscript; available in PMC: 2015 Oct 28.
Published in final edited form as: J Am Chem Soc. 2015 Apr 1;137(14):4823–4830. doi: 10.1021/jacs.5b01549

Figure 3.

Figure 3

Rheological properties of cross-linked peptide hydrogels. Higher concentrations of negative ion charge shield MDP charges to a greater extent, yielding increased storage moduli (G′) and loss moduli (G″). Significant increases were noted when PO43− concentration was increased, compared to prior values (*, 5 mM PO43− from Galler et al., G′ (dashed line), G″ (dotted line)).2 Increasing the density of PO43− groups, using bisphosphonate clodronate (Clod.), resulted in an increase in mechanical strength. Charge density did not result in significantly increased moduli when comparing heparin (Hep.) and trypan blue (Tryp.) at similar concentrations. Charge density and conformation of suramin resulted in an order of magnitude increase in mechanical strength with increase in concentration. Similar Greek letter indicates no statistically significant difference for each receptor (*, p < 0.01).