Figure 1.
(A) Cellink BioX6 extrusion-based bioprinter; (B) Bioprinted vascular constructs.
Table 1.
Bioprinting parameters.
| Parameter | Range of Values |
|---|---|
| Cell density | 1 × 105 cells/ml–3 × 106 cells/ml |
| Nozzle diameter | 22 gauge |
| Print speed | 7 mm/s |
| Printhead temperature | 23.5°C |
| Print bed temperature | 15°C |
| Layer height | 0.41 mm |
| Pressure | 40–75 kPa |
| Infill density | 40% |
| Cross-linking: frequency | After every layer |
| Cross-linking: time (per instance) | 10 s |
| Cross-linking: wavelength | 405 nm |
| Cross-linking: distance to center of build | 4 cm |
Figure 2.
Setup for simulated microgravity experiments. (A) Slide flask containing a bioprinted vascular construct; (B) RPM supporting bioprinted tissue constructs housed inside an incubator (NASA KSC Microgravity Simulation Facility).
Figure 3.
Cellular viability of bioprinted vascular tissue constructs from 1 to 9 days after bioprinting.
Figure 4.
Confocal microscopy imaging for visualizing live (green) and dead (red) cells in bioprinted constructs after bioprinting. (A) Day 1; (B) Day 3; (C) Day 5; (D) Day 7; (E) Day 9; (F) Z-stack fluorescent images corresponding to day 9.
Figure 5.
Normalized fluorescent intensity profiles for detecting ROS levels in fibroblast cells exposed to simulated microgravity for 24, 48, and 72 h. (A) Bar plot of normalized fluorescence intensity values showing a time-dependent increase in ROS levels; (B) Box plot representing the distribution of normalized fluorescence intensity values across all samples for each condition.
Table 2.
t-test results comparing ROS levels across time points.
| Comparison | t-statistic | p-values | Interpretation |
|---|---|---|---|
| Control vs. 24 h | −20.74 | 0.0000319 | significant |
| Control vs. 48 h | −59.20 | 0.0000005 | highly significant |
| Control vs. 72 h | −4.40 | 0.0117 | significant |
Figure 6.
Confocal microscopy images showing oxidative stress in the samples: (A) Control; (B) Simulated microgravity exposure for 24 h; (C) 48 h; (D) 72 h.