Evaluating hPDLSCs Viability on Ceramic Scaffolds

The hPDLSCs of passage 4 were cultured on HA and mnHA samples for 1, 4, and 7 days, respectively. The three pieces of cell/ceramic constructs in each group were assessed for the cell vitality by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT; Sigma-Aldrich) assay as previously reported.18 (link) Then 400 μL α-MEM supple mented with 40 μL of 5 mg/mL MTT solution was added into each well followed by sample incubation at 37°C to allow formazan formation. Four hours later, the solution with MTT was discarded and replaced by 400 μL dimethyl sulfoxide (DMSO, Sigma-Aldrich) to dissolve the formazan crystals. The optical density was measured at 490 nm on the Multi-Detection Microplate Reader (Bio-tek, Winooski, VT, USA). In the meantime, an additional standard curve for MTT assay was performed. As previously reported, the cells were seeded in 96-well plates with different densities of 5×10³, 1×10⁴, 1.5×10⁴, 2×10⁴, and 2.5×10⁴ cell/well and cultured in α-MEM, and then the cell number was quantified by a cell standard curve.32 (link) All experiments were conducted in triplicate.