Page 212 - IJB-10-5

International Journal of Bioprinting Biomimetic osteochondral scaffold

composite struts were used to build the subchondral layer 3.2. Characterization of integrated
to facilitate osteogenic differentiation of rBMSCs, while the osteochondral scaffolds
cryogenic 3D-printed FGF-18/P(DLLA-TMC) framework, The macroscopic and microscopic morphology of the
which was further filled with GelMA hydrogel, was used as osteochondral scaffold without cell seeding is displayed
the cartilage layer to promote chondrogenic differentiation in Figure 2A and B. The subchondral layer exhibited a
of rBMSC microspheres. The sustained delivery of BMP- regular grid-like pattern, and each strut had a microporous
2 and FGF-18 at the subchondral and cartilage layers, structure, in which secondary micropores with a diameter
respectively, was designed to match the requirements of of 8.10 ± 1.87 μm and β-TCP particles were uniformly
regionally effective osteogenesis and chondrogenesis. The dispersed on the strut surface. The micromorphology of
designed interface layer mimics the dense non-porous the interface layer was similar to the subchondral layer and
calcified anatomy of native osteochondral interface tissue had no macroporous grid structure, as a compact structure
and prevents the mutual interference of BMP-2 and FGF- can be used as a barrier. The cartilage layer consisted of a
18, thereby achieving the spatially controlled release of P(DLLA-TMC) frame, with a latticed structure comprising
GFs. Through cryogenic 3D printing and subsequent numerous secondary micropores, and GelMA hydrogel
lyophilization, the three different layers were tightly blocks, which exhibited a loose and porous structure.
bonded together, which could spatiotemporally direct The digital and SEM images of the osteochondral scaffold
osteogenic/chondrogenic differentiation of rBMSCs. revealed that the three layers (subchondral, interface, and

Figure 2. Characterization of integrated osteochondral scaffolds. (A) Digital images and (B) scanning electron microscope (SEM) images displaying
the macro- and micromorphology of different layers within osteochondral scaffolds, respectively. (C) Stress–strain curves and (D) Young’s modulus of
osteochondral scaffolds under wet conditions at 37°C. (E) Degradation of osteochondral scaffolds in a shaking water bath at 37°C and 80 rpm. *p < 0.05.
Scale bars: (A) XXX. Magnification: (B, top) ×50; (B, bottom) ×1000.

Volume 10 Issue 5 (2024) 204 doi: 10.36922/ijb.3229