Fbmtm basal medium

Normal human lung fibroblasts (NHLF) were purchased from Lonza (catalog number CC-2512), IPF-derived fibroblasts (LL97A) were purchased from ATCC (catalog number ATCC-CCL-191), and NSIP-derived fibroblasts (MN) were obtained from the patient sample, using the protocol described in the Section 2.2. All cell lines were cultured in a fibroblast-dedicated culture system containing FBM^TM Basal Medium (Lonza, Basel, Switzerland, catalog number CC-3131), and FGM^TM SingleQuots^TM supplements (Lonza, catalog number CC-4126) in culture flasks, in a CO₂ incubator providing 95% air/5% CO₂ atmosphere. The control glass sample, as well as the soft and stiff PDMS substrates attached to glass coverslips, were placed into a Petri dish (35 mm in diameter). Then, they were sterilized for one hour under UVC light (germicidal lamp, λ = 254 nm), in a laminar flow chamber (Nu425, NuAire). After sterilization, a solution of cells (80,000 cells per mL of the culture medium) was placed over glass or the PDMS surface. Next, the Petri dish was incubated in the CO₂ incubator for 1, 3 and 6 days. To prove the reproducibility of the results, the experiments were repeated at least three times for each cell line and time-point. For each experimental sequence, two or three identical samples were prepared and measured.

Primary human skin fibroblasts (LONZA, CC-2511 NHDF) were cultured in the FGM-2 Fibroblast Bullet Kit medium with FBMTM Basal Medium (CC-3131, Lonza), FGMTM-2 SingleQuotsTM supplements (CC-4126, Lonza), and a mixture of antibiotics (Pen/Strep/Fungizone, 17-745E, Lonza) in a tissue culture incubator (INCOmed 153, Memmert) in an atmosphere of 5% CO₂ at 37°C and 90% humidity. For experiments, cultured cells were thawed between passages 4 and 7, and cell growth was monitored under an inverted microscope (Nikon TS2RFL). The cell density at seeding was approximately 4 x 10⁴ cells/well on the 6-well culture plate. The volume of medium used in each well was 2.0 mL and was mentioned the next day.

Normal Human Ventricular Cardiac Fibroblasts (NHCF-V, CC-2904, Lonza) were cultured according to the recommended protocol. In brief, cells were grown in FBM^TM Basal Medium (CC-3131, Lonza) supplemented with FGM^TM-3 SingleQuot (CC-4525, Lonza) and 1× penicillin-streptomycin (Life Technologies) at 37 °C in a humidified atmosphere containing 5% CO₂.