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International Journal of Bioprinting Biocompatible materials and Multi Jet Fusion

Figure 7. Viability of normal human knee articular chondrocytes (1 × 10 cells∙mL ) bioprinted with 0.75% alginate_4.0% gelatin_1.4% CCNC bioink
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assessed by LIVE/DEAD assay (Invitrogen). (A) Viability at different time points. (B) Changes in cell count during culture. Note: *P value ≤ 0.05; **P value
≤ 0.02. (C) Representative 3D confocal scans from the constructs.
Figure 6A and C). The meniscus-like shape model was also 3.4. Gene expression
bioprinted (Figure 6D). The RNA isolation resulted in a low nucleic acid yield;
therefore, only five chondrogenesis marker genes were
3.3. Cell viability selected from previous research . Figure 8 shows the
[5]
The cell viabilities at all time points were above 98% changes in gene expressions. There were no significant
(Figure 7A); however, there was a significant drop in cell alterations to the expressions of COL1A1 and COL10A1
count after one week (Figure 7B). Figure 7C represents during the investigated time. On the other hand, the
the 3D confocal scans from the constructs. Since each expression of COL2A1 increased during culture in the
scan has a different layer number, it could be mistakenly bioprinted construct, with a significant change after four
deduced that the cell quantity is the same. We also noticed weeks. It resulted in a high COL2A1/COL1A1 ratio. In
cell release from the construct under optical microscopy. terms of transcription factor genes, SOX9 and RUNX2
The homogenous cell distribution inside the construct expressions were higher after bioprinting but decreased
indicates a successful mixing process.

Volume 9 Issue 1 (2023) 7 https://doi.org/10.18063/ijb.v9i1.621