Materials

Collagen type I aqueous solution was kindly supplied by Nitta Gelatin Co. (Osaka, Japan). Human pulmonary fibroblasts (HPFs), fibroblast growth medium 2 (FGM2), and fetal bovine serum (FBS) were purchased from Takara Bio Inc. (Shiga, Japan). Cell Count Reagent SF and HEPES were purchased from Nacalai Tesque Inc. (Kyoto, Japan ). A mouse lung fibroblast cell line (Mlg2908), a human alveolar adenocarcinoma cell line (A549), and a mouse alveolar epithelial cell line (MLE-12) were purchased from ATCC (VA, USA). F12K media were purchased from ATCC (VA, USA). L-Glutamine, solution (200 mM) was purchased from (Thermo Fisher Scientific Inc., MA, USA). Insulin, sodium selenite and β-estradiol were purchased from Sigma-Aldrich Japan K.K. (Tokyo, Japan). A Transferrin was purchased from BD Japan (Tokyo, Japan). A hydrocortisone was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). A mixture of 10,000 U penicillin and 10 mg/mL streptomycin (Pen-Strep) and poly(vinyl alcohol) (PVA; average molecular weight: 85,000–124,000; 87%–89% hydrolysed) were purchased from Merck KGaA (Darmstadt, Germany). Dichloromethane (DCM), DMEM/Ham’s F-12 (DMEM/F12), PLGA-5005, and 4% paraformaldehyde in phosphate-buffered saline (4% PFA/PBS) were purchased from Fujifilm Wako Pure Chemical Corporation (Osaka, Japan). Fragmin was purchased from Kissei Pharmaceutical Co. Ltd. (Tokyo, Japan).