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International Journal of Bioprinting DEX-Loaded PLGA microspheres enhance cartilage regeneration

Figure 8. Mechanical and biochemical properties of constructs on day 14, including Young’s modulus and glycosaminoglycan (GAG) content. (A) Young’s
modulus of the five groups of constructs on day 14 (n = 3). (B) Glycosaminoglycan (GAG) content of constructs in each group (n = 3).

control group. Among these four groups, the PLGA-dex30 smooth filament extrusion, by utilizing a 400 μm diameter
MPs@GelMA group exhibited the highest chondrogenic nozzle. The printability results for the five different
ability. Concerning anti-inflammatory capacity, a bioink groups are depicted and described in Figure S1
combined analysis of capsule thickness and inflammation- (in Supplementary File).
related RT-PCR results indicated that as the DEX The constructs were evaluated in terms of interlayer
concentration increased, the anti-inflammatory capacity adhesion, shape stability, surface smoothness, and
improved. In other words, the PLGA-dex60 MPs@GelMA structural morphology (Figure 9A). Notably, both groups
group demonstrated the strongest anti-inflammatory retained their intended shapes well. After printing
ability, while the PLGA-dex30 MPs@GelMA group showed six layers, there were no instances of local collapse or
a slightly weaker anti-inflammatory ability. Therefore, deformation within any structure. Interlayer connections
the PLGA-dex0 MPs@GelMA group was designated as remained secure, with no instances of slipping or
the control, while the PLGA-dex30 MPs@GelMA group detachment throughout the printing process. 31–33 Both
served as the experimental group for 3D bioprinting. the PLGA-dex0 MPs@GelMA and PLGA-dex30 MPs@

To evaluate the printability of each bioink, tests GelMA groups exhibited distinct square cross-sections
were performed under controlled conditions at a room at the second, fourth, and sixth layers, showcasing more
temperature of 20–22°C. The nozzle temperature was uniform and smoother extrusion lines. The surface of
maintained at 19°C, and the platform temperature was set these lines appeared smoother, and the voids within the
at 23°C. The extrusion pressure was fine-tuned to achieve grid printing structure exhibited more even and regular

Volume 10 Issue 5 (2024) 396 doi: 10.36922/ijb.3396