Figure 4.

Astrocyte activation can be controlled via integrin-binding and MMP-degradable peptides in the brain hydrogel. a) Box and whisker plots show distance of process length from the cell center as a function of the integrin-binding peptide concentration (in mm) in the hydrogel, with collagen gels as a comparison. N = 2, n = 3. b) Normalized fluorescence intensity of glial fibrillary acidic protein (GFAP) as a function of integrin-specific peptide concentration, with both collagen gels and a glass coverslip for comparison (N = 3). All hydrogels in (a) and (b) had 25 mol% MMP-degradable peptides and the time point is 48 h after encapsulation. c) Box and whisker plots showing distance of process length from the cell center as a function of both integrin-binding peptide concentration and concentration of the MMP-degradable peptides. Statistics are in comparison to a PEG hydrogel with no peptides included (negative control). N = 2, n = 4. d) Normalized GFAP fluorescent intensity as a function of hydrogel integrin-binding and MMP-degradable peptide concentrations. N = 2, n = 4. Data in (c) and (d) are after 72 h of encapsulation. e) Representative images of astrocytes encapsulated in different hydrogel conditions after 72 h. Scale bar is 20 μm. Data in (a)–(c) are mean + s.d. Data in (d) are mean + SEM. Data in (a)–(d) were analyzed using a one-way analysis of variance (ANOVA) followed by a Dunnett’s multiple comparison test with 95% confidence interval. *, **, ***, and **** indicate P < 0.05, P < 0.01, P < 0.001, and P < 0.0001. N.S. is not significant.