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International Journal of Bioprinting Enhanced osteogenesis in gelatin releasing bioink

after fabrication and after 3 weeks of culturing in cell of releasing. Therefore, we assumed that the release of
culture media at 37°C. The MA-alginate hydrogel that gelatin resulted in empty spaces in the hydrogel structure
did not contain gelatin showed a similar ratio of swelling and that these newly empty spaces could be filled by water
immediately after fabrication and after 3 weeks of molecules, which would increase the water content of the
immersion in cell culture media. However, some hydrogels hydrogel.
that contained gelatin showed improvement in the
swelling ratio after 3 weeks. In Figure 2a, it can be noted To verify the mechanical property of the hydrogels,
that there were no significant differences in the swelling compressive moduli were measured at each time point
property between every group of hydrogel immediately (0 day, 1, 2, and 3 weeks). Samples from every hydrogel
after fabrication, which indicated that the amount of group (10:0, 9:1, 7:3, and 5:5 MA-alginate/gelatin ratio)
gelatin had no effect. However, after 3 weeks in cell culture were immersed in the same conditions as those used for
media, and 3 weeks of gelatin release, an improvement in water content measurement. The compressive modulus
the swelling property was noted for the 7:3 and 5:5 MA- of the MA-alginate and 9:1 MA-alginate/gelatin hydrogel
alginate/gelatin hydrogel groups (Figure 2b). The scanning decreased after immersion in media due to their swelling
electron microscopy analysis was performed for a few property, as shown in Figure 3a and 3b. Also, as shown
times to look for any microstructures changes caused in Figure 3c and 3d, the 7:3 and 5:5 MA-alginate/gelatin
by gelatin releasing; however, there were not much of hydrogels had a lower compressive modulus immediately
differences between hydrogel groups even for after 3 weeks after fabrication compared to the other two groups due

Figure 3. Compressive moduli during gelatin releasing of each hydrogel for 3 weeks of releasing. (a) 10:0 MA-alginate/gelatin. (b) 9:1 MA-alginate/gelatin.
(c) 7:3 MA-alginate/gelatin. (d) 5:5 MA-alginate/gelatin. *P < 0.05, n.s. = not significant.

Volume 9 Issue 2 (2023) 147 https://doi.org/10.18063/ijb.v9i2.660