Flag 14793

Ursodeoxycholic acid (UDCA, 15121) was purchased from Cayman Chemical (Ann Arbor, MI, USA). MTT [3(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (M5655), DAPI (D9542) and bovine serum albumin (BSA, A3059) were purchased from Sigma Chemical Co. (St. Louis, MO, USA). CellTiter-Glo® Luminescent cell viability assay kit (G9241) was purchased from Promega Co. (Madison, WI, USA). Mouse antibodies which are reactive with acetylated tubulin (T7451) were from Sigma-Aldrich Co. (St. Louis, MO, USA). Polyethylenimine (PEI, 02371) was purchased from Polysciences, Inc. (Warrington, PA, USA). Rabbit antibodies which are reactive with Flag (14793) were from Cell Signaling Technology Inc. (Danvers, MA, USA). FITC-conjugated streptavidin (554061) and PE-conjugated streptavidin (554060) were purchased from BD Bioscience (Franklin Lakes, NJ, USA). Flag-tagged human pCMV-ACE2 plasmid (HG10108-CF) and a biotinylated SARS-CoV-2 (2019-nCoV) spike protein, RBD (40592-V08B-B) were purchased from Sino Biological Inc. (Wayne, PA, USA). Fibronectin (5050) and bovine collagen type I (5005) were purchased from Advanced BioMatrix, Carlsbad, C, USA). Except where indicated, all other materials are obtained from the Sigma Chemical Co. (St. Louis, MO, USA).