Table 2.
Comparison of the results obtained for 3D spheroids of RT4 cells generated by forced floating and hanging drop methods.
| 3D methods | ||
|---|---|---|
| ULA | HD | |
| Spheroidization time | Between 24 and 48 h | Between 24 and 48 h |
| Morphology | Round-type | Round-type |
| Presence of microvilli | Yes | Yes |
| Roundness | 0.75–0.95 | 0.85–0.90 |
| Solidity | Regular surface (>0.95) | Regular surface (>0.95) |
| Sphericity Index | Ellipsoidal/Spherical shape | Ellipsoidal/Spherical shape |
| Diameter ranging: 300–500 μm | Cultures seeded with 0.5 and 1.25 × 104 cells/mL | Cultures seeded with 2.5 and 3.75 × 104 cells/mL |
| Fold increase (FI) | Lower than 2Da Similar to HD | Lower than 2Da Similar to ULA |
| Number of apoptotic cells | 120 h: similar to 2D | 120 h: similar to 2D |
| 168 h: similar to 2D | 168 h: higher than 2Db | |
| Metabolism | Reduced compared to 2D | Reduced compared to 2D |
| IC50 value | Higher than IC50 of 2Dc | Higher than IC50 of 2Dd |
| Cell plating | Easy | Difficult |
| Culture maintenance | Easy | Difficult |
| Real-time monitoring | Easy | Difficult |
| Medium change | Trivial | Not trivial |
| Possibility of performing assays directly in the plates | Yes | No |
a
One-way ANOVA statistic method with post-hoc test Tukey HSD (P < 0.001).
b
One-way ANOVA statistic method with post-hoc test Tukey HSD (P < 0.005).
c
Extra-sum-of-squares statistic method with F-test (P < 0.001).
d
Extra-sum-of-squares statistic method with F-test (P < 0.05 for HD cultures seeded with 2.5 × 104 cells/mL and P < 0.001 for HD cultures seeded with 3.75 × 104 cells/mL).