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.