2.7. Cell viability using Alamar Blue assay
Alamar Blue (AB) assay was used to quantitively measure the metabolic activity of living cells on the scaffolds by detecting the oxidation-reduction rate of AB reagent [36]. The effects of cell seeding density and coating condition of the various 3D porous scaffolds on the viability of DPSCs were evaluated. Briefly, after 24 and 48 hours of cell seeding on scaffolds, 1 mL of 10% AB solution was added to each well (250 µL/well). The plates were shaken gently (200 rpm) for 5 min and incubated for 4h at 37 °C with 5% CO2. After incubation, 100 μL of each sample was transferred to a 96-well plate and the fluorescence intensity was recorded at an excitation wavelength of 540 nm and an emission wavelength of 600 nm using a spectrophotometer (BioTek Synergy H1 multi-mode reader). Non-seeded scaffolds supplemented with 10% AB dye were used as a negative control to confirm that the fluorescence intensity of scaffolds alone did not interfere with the assay. Each experimental condition was conducted in triplicates, and experiments were replicated twice.