Figure 2.

(a) Total soluble protein concentration measured in the supernatant of healthy and bleomycin-injured murine lung dECM samples during pepsin digestion over time. Total protein concentration increased from initial measurement to 4 h then plateaued (N = 4, ANOVA, Tukey Test). (b) quantification of free amine concentration over time showed that peptide bond cleavage increased with pepsin digestion time (N = 4, ANOVA, Tukey Test). Protein fragment size quantification for both (c) healthy and (d) bleomycin-injured murine lung dECM showed pepsin digestion was required to solubilize dECM proteins to fragments ranging in size from 10 to 75 kDa. Despite decreases in band intensity over time for healthy (4–36 h) and bleomycin-treated (24–26 h) qualitative results showed large protein fragments were solubilized for functionalization and incorporation into hybrid-hydrogels (N = 4).