3.2. Physical and mechanical properties of DP
The surface topographies of collagen, NP, and DP scaffolds were
visualized by SEM and AFM (Figure 2A&B). As shown in the SEM images, NP
had a relatively smooth surface, while COL and DP displayed uneven and
porous surfaces with abundant collagen fibers randomly arranged in a
network pattern. Masson trichrome staining revealed the collagen fiber
structure in each group (Figure 2C). The structure and distribution of
collagen did not differ significantly between DP and NP. Picrosirius red
examination also showed that the arrangement and structure of collagen
in DP was similar to that in NP (Figure 2D). Immunohistochemical
staining of collagen I demonstrated the arrangement of type I collagen
in each group (Figure 2E), and Safranin O staining showed the presence
of identifiable GAGs in DP scaffolds after decellularization (Figure
2F). The surface hydrophilicity of each scaffold material was analyzed
by water contact angle measurement as shown in Figure 2G. Both the NP
and DP scaffolds showed good hydrophilicity. Analysis of the mechanical
properties of each scaffold type showed no significant difference in
yield stress among the groups, but that the DP scaffolds exhibited a
moderate elastic modulus (Figure 2H).