Page 317 - IJB-9-5

International Journal of Bioprinting Scaffold for engineering enthesis organ

Figure 12. MSCs osteogenic/tenogenic differentiation support by the enthesis scaffold. (A) Schematic representation of protocol used. (B, C) MSCs or
pre-differentiated MSCs (PRE-MSC) were seeded on the enthesis scaffold (Enthesis) or plastic (CTRL) and maintained in a growth medium. (B) After
14 days of differentiation, alizarin Red staining was performed. (C) After 21 days of differentiation, aniline blue staining was performed. Representative
images were shown. Data are the results of three independent experiments. * p < 0.05, ***p < 0.001 vs. ND; § p < 0.05, §§ p < 0.01; # p < 0.05, ## p < 0.01,
### p < 0.001 vs. CTRL.

toe, (ii) the linear, and (iii) the yield regions . The stress are as follows: E = 235 ± 15 MPa, σ max = 8 ± 0.25 MPa,
[45]
slowly increases with strain within the toe region (0%– ε max = 65% ± 12%, and U = 1.03 ± 0.25 × 10 J/m . These
3
6
7% strain). This non-linear behavior can be related to the data are in line with the literatures. As reported in the
braided structure. During the initial phase of loading, work of Ramakrishna et al. , researchers fabricated
[50]
the fiber bundles start to align from a wavy shape. electrospun braided scaffolds made of poly(lactic acid)
They elongate according to the direction of the applied (PLA) with Young’s modulus of in a range of 300–800
uniaxial force. The force is progressively transmitted to MPa. Mechanical parameters are also comparable to the
the interconnected fiber bundles and their component in vivo tissues such as the Achilles Tendon (AT), which
nanofibers, resulting in linear mechanical behavior with are presented as E = 266 ± 106 MPa and ε max = 48% ± 15%.
a constant elastic modulus in the linear region (7%–12% The ultimate stress of the AT remains significantly higher,
strain). As the applied stress increases, the yield region is with a value of 47 ± 17 MPa, as reported in the study by
reached, extending the strain from 13% to approximately Brennan et al. . In addition, the fabricated clinically-
[45]
65%. At this stage, the woven fiber bundles reached relevant scaffolds have the unique characteristic of being
maximum alignment, starting to deform plastically until triphasic, while braided scaffolds in the literature present
failure. The mechanical parameters of braided scaffolds a single phase.

Volume 9 Issue 5 (2023) 309 https://doi.org/10.18063/ijb.763