Figure 9B. SEM images showing cell infiltration of C2C12 cells cultivated onto cellulose acetate nanofiber (A) and cellulose acetate nanofiber with annatto extract (B) after seven days. Scale bars indicate 20 µm.
Cell density increased exponentially after 7 days of culture to cover the surface of the nanofibers (Figure 9A). This corroborates the findings of the MTT test, in which viability for cells cultured onto the scaffolds was higher after 7 days of culture due to cell proliferation (Figure 7B). Almost all the cells stretched along the nanofibers and exhibited elongated morphology on the CA and CA@A nanofibers. According to Gurdon et al. (1996) [46], the community effect is a phenomenon involved in myogenesis in which muscle precursor cells must contact a sufficient number of like neighbors in order to undergo coordinated differentiation within developing tissue. Our findings indicate that cell-cell communication may play an important role in myogenic differentiation. Myoblasts covered by nanofibers were also present, suggesting cell migration through the pores of the scaffold (Figure 9B) and indicating that the porous nature of nanofiber scaffolds is ideal for myoblasts to infiltrate and may allow vascularization as well as multiple layers of skeletal muscle cells to form, both crucial processes for establishing a tissue-like construct [46].