Rpmi 1640 culture medium

The human cell lines A549 and HT29 were purchased from the American Type Culture Collection (ATCC) (Manassas, VA, USA) and Korean Cell Line Bank (Seoul, Republic of Korea). RPMI 1640 culture medium (GenDEPOT Inc., Barker, TX, USA), supplemented with 10% fetal bovine serum (FBS; Thermo Fisher Scientific, Waltham, MA, USA), was used to grow the cell lines at 37°C in a humidified incubator with a 5% CO₂ atmosphere. Cell viability was determined by MTT assay. For MTT assay, cells were seeded in 96-well plates at a density of 1×10⁵ cells/mL. After 24 hours of incubation, the cells were treated with various concentrations of BSA-Rh2 NPs and standard ginsenoside Rh2 for 24 hours. After incubation, 10 μL of the MTT stock solution (5 mg/mL) was added to each well and incubated for 4 hours. Then, the supernatants were removed and replaced with 100 μL of dimethyl sulfoxide (DMSO). The amount of formazan formed by viable cells was measured using multi-model plate reader (BioTek Instruments, Winooski, VT, USA) at a test wavelength of 570 nm with a reference wavelength of 630 nm. In addition, cytotoxicity assay was conducted in HaCaT skin cell lines to analyze the cell viability.31 (link)