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International Journal of Bioprinting 3D printing of collagen II-scaffolds

Figure 12. Immunostaining images of gelatin- (A) and collagen I-based (B) scaffolds with a rod distance of 450 μm, (C) collagen II-based nonporous
bulk scaffolds, and (D–F) collagen II-based scaffolds with a rod distance of 320 (D), 450 (E), and 550 μm (F), respectively. DAPI staining: blue; collagen II
staining: green. Abbreviation: DAPI, 4’,6-diamidino-2-phenylindole.

could be attributed to a higher number of cells (based hypoxic condition in scaffolds with smaller pores
on CCK-8 results, Figure 9) in scaffolds with smaller may be attributed to a higher number of cells and
pores. According to the random walk model, a enhanced cell condensation. Moreover, smaller
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higher number of junctions in mesh scaffolds favors pores may also reduce oxygen transportation to cells.
cell migration, and scaffolds with smaller pores also Several studies using 3D-printed mesh scaffolds have
have more junctions, making them more favorable investigated the effects of pore size on the proliferation and
for cell migration and subsequent cell condensation.
chondrogenic differentiation of MSCs. Smaller pore sizes
(ii) The upregulated expression of HIF-1α in scaffolds generally favor chondrogenic differentiation but hinder
with smaller pores suggests favorable chondrogenic cell proliferation. For example, Di Luca et al. reported
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differentiation in these scaffolds. In this regard, the upregulated expression of ACAN, collagen II, and SOX-9
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Volume 10 Issue 5 (2024) 287 doi: 10.36922/ijb.3371