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International Journal of Bioprinting Skin bioprinting: Keratinocytes and stem cells

Figure 12. Viability and metabolic activity of co-cultured constructs. (A) Cell viability of biofabricated constructs containing HaCaT and ADSCs on days
(d) 1, 4, 7, and 14 (n = 3). (B) Metabolic activity of HaCaT and ADSCs within printed constructs on days 1, 4, 7, and 14 (n = 3). (C) HaCaT and ADSCs in
Alg/HA/Gel and Alg/HA/Fib on days 1, 4, 7, and 14. Scale bars: 100 μm. Green indicates living cells; red indicates dead cells. Data are represented as mean
± standard deviation; *p ≤ 0.05. Abbreviations: ADSC, adipose-derived stem cell; Alg, alginate; Fib, fibrin; Gel, gelatin; GelMA, gelatin methacryloyl; HA,
hyaluronic acid; ROI, region of interest.

Time significantly impacts the degradation process. All combined metabolic activity, compared to 50% for the
constructs displayed a significantly higher area on day 1 GelMA control group. Analyzing the metabolic rate over the
compared with days 7 and 14, independent of hydrogel and entire test period using two-way ANOVA and unpaired t-test
cell composition. Furthermore, all experimental groups revealed significant differences over time for cells within the
significantly decreased in size from day 4 to 14. Cell-laden biofabricated constructs and those at the well bottom.
constructs significantly degraded from day 1 to 4 and from Cells at the well bottom displayed a significant difference
day 7 to 14.
between day 14 and days 1, 4, and 7 for experimental groups
3.3.2. WST-8 assay Ib (Alg/HA/Gel and Alg/HA/Fib with HaCaT and ADSC),
The metabolic activity of the bioprinted samples and cells Ic (Alg/HA/Gel and Alg/HA/Fib with HaCaT), and IIb
at the well bottom was measured on days 1, 4, 7, and 14 (GelMA and Alg/HA/Fib with HaCaT and ADSC). On
(Figure 10). day 14, the cells of group Ic (Alg/HA/Gel and Alg/HA/Fib
with HaCaT) at the well bottom exhibited a significantly
All printed constructs displayed a steady increase in
metabolic activity regardless of cell composition or choice higher metabolic activity than those of group IIc (GelMA
and Alg/HA/Fib with HaCaT) (Figure 11A).
of hydrogel over the experimental period. Likewise, the
metabolic activity of cells at the well bottom increased for all Additionally, for the cells at the well bottom, Alg/
experimental groups until day 14. On day 14, the metabolic HA/Gel displayed a significantly higher metabolic rate
activity of the constructs composed of Alg/HA/Fib with compared with GelMA on day 1. HaCaT and ADSCs at
HaCaT and ADSC in co-culture accounted for 37% of the the well bottom were differentiated according to their

Volume 10 Issue 6 (2024) 274 doi: 10.36922/ijb.3925