Fig. 3.

Comparison of VEGF binding with VBP and VBP_WT microspheres in the presence and absence of protease inhibitor. (A) Microspheres at 1.6 and 0.4% peptide densities, as well as Blank microspheres, were incubated in 25% FBS with and without protease inhibitor cocktail (PI). Data are presented as bound VEGF (ng VEGF per mg microspheres) with protease inhibitor (+PI) divided by bound VEGF without protease inhibitor (—PI). A one-tailed Student’s t-test was performed to test if these values were significantly greater than 1, with asterisks denoting p < 0.05. (B) Comparison of effective dissociation constant for VBP and VBP_WT microspheres preincubated in 25% serum with or without protease inhibitor. A two-tailed Student’s t-test was performed between VBP and VBP_WT microspheres with no preincubation vs. each respective condition with serum preincubation. Asterisks denote p < 0.05. (C) Comparison between different UFH-containing solutions both in a UFH or albumin-only preincubation step or with UFH or albumin-only in the presence of VEGF. Data are presented as bound VEGF per mass of 1.6% peptide microspheres in ng mg⁻¹ for VBP (white bars), VBP_WT (black bars), Scramble (dark gray bars) or Blank (light gray bars) microspheres. No statistical significance existed between preincubation conditions, and in all cases VBP and VBP_WT microspheres bound significantly more VEGF than Scramble and Blank. (D) Comparison of VEGF-binding dissociation constants of heparin-containing medium, K_D,heparin, divided by the same of albumin-only medium, K_{D,albumin-only}, for both preincubated microspheres and for no preincubation. Statistical significance is depicted as significantly less than 1 with a one-tailed Student’s t-test, with asterisks denoting p < 0.05.