Glomax multi detection reader spectrophotometer

hPDLSCs were seeded in 96-well flat-bottom plates at a density of 1 × 10³ cells/well. After 24 h, cells became confluent, the medium was replaced, and cells were incubated for 6–24 and 48 h in presence of ELF-EMF. Cell viability and proliferation were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay according to the manufacturer's recommendations (Merck KGaA, Darmstadt, Germany). At the end of incubation, MTT reagent was added for 2 h and incubated at 37 °C, and absorbance was assessed at OD590 nm using a Glomax multi-detection reader spectrophotometer (Promega, Milan, Italy). Absorbance data were normalized to the unexposed control group, which was considered 100% of viability.

Levels of 25(OH)D₃ (Cayman Chemical, Michigan, USA), TGFβ (Boster, Pleasanton, CA, USA), IL-35 (Elabscience, Houston, USA), IL-17A (Diaclone, Besancon, FR), and MMP9 (BioVendor, Brno, CZ) were assayed by the ELISA technique using a manufacturer kit. The limits of detection were 25(OH)D₃ and MMP9, <0.5 ng/mL; TGFβ, IL-35, and IL-17A ≤ 1 pg/mL. For all assays, absorbance was assessed using a Glomax multidetection reader spectrophotometer (Promega, Milan, Italy).