Fig. 1

Characterization of soluble tendon- and cartilage-derived extracellular matrix. a–d Prior to decellularization, nuclei are clearly present in native tendon and cartilage tissues, as shown through H&E and DAPI staining. e–h Following decellularization, no nuclei are visible. Scale bar = 200 μm. i dsDNA contents were significantly reduced in decellularized tissues compared to native tissues (p < 0.001, n = 8). j Collagen content in native and decellularized tendon was equivalent, but was increased in decellularized cartilage vs. native cartilage (p < 0.05, n = 8). k Sulfated glycosaminoglycan (sGAG) content was higher in cartilage tissues than tendon tissues, regardless of decellularization step (p < 0.05), but decellularized cartilage contained significantly less sGAG than native cartilage (p < 0.001, n = 8). For (i–k), statistically significant differences are indicated by overlying horizontal lines. l Urea extraction yielded an insoluble and soluble fraction. The soluble supernatant (yellow line) was collected. m Pepsin digestion yielded a homogeneous slurry. n,o SDS-PAGE analysis of tendon (n) and cartilage (o) tissues at different stages of decellularization and solubilization. cAP acid-pepsin digested cartilage extracellular matrix, cECM urea-extracted cartilage extracellular matrix, tAP acid-pepsin digested tendon extracellular matrix, tECM urea-extracted tendon extracellular matrix