Figure 7

Degradation and swelling degree, and ATR-FTIR spectra of different collagen hydrogel groups. (a) Degradation and (b) swelling degree of collagen, 2-Col/PA-CH (Cross-linked 2 mg/collagen hydrogel with 0.5% proanthocyanidin and calcium hydroxide), and 2-Col/PA-CH/Mic EpoB (Cross-linked 2 mg/mL collagen hydrogel with 0.5% proanthocyanidin and calcium hydroxide and 2.5 ng/mL Epo B microspheres) hydrogels in DEME-F12 at 37 °C (The time duration: 14 days for degradation test and 4 days for swelling test). *P < 0.05, **P < 0.01, ***P < 0.001. (c) The consistency in cross-linked collagen hydrogels. (d) The ATR-FTIR spectra of PA, collagen, 2-Col/PA, 2-Col/PA-CH and, (e) their second-derivative spectra in the amide B region. The main peaks are shown by red arrows and gray dash lines. The second-derivative spectra in the amide B region indicate secondary structure conformational changes in the two cross-linked hydrogels scaffold (2-Col/PA and 2-Col/PA-CH) compared to the collagen (uncross-linked) hydrogel scaffold.