Anti k8

The cell-printed structure was harvested and fixed with a solution of 4% paraformaldehyde. The structure was embedded in optimal cutting temperature (OCT) compound (Sigma-Aldrich, USA) and sectioned 10-mm thick by using a cryotome (Leica, CM1950, Germany). The sliced samples were washed repeatedly with PBS solution to remove OCT compound and then permeabilized with a solution of 0.1% Triton X-100 (Sigma-Aldrich, USA) in PBS for 5 min. To reduce nonspecific background, sections were treated with 0.2% bovine serum albumin (Sigma-Aldrich, USA) solution in PBS for 20 min. To visualize iSGCs, sections were incubated with primary antibody overnight at 4°C for anti-K8 (1:300), anti-K14 (1:300), anti-K18 (1:300), anti-K19 (1:300), anti-ATP1a1 (1:300), anti-Ki67 (1:300), anti–N-cadherin (1:300), anti–E-cadherin (1:300), anti-CTHRC1 (1:300), or anti-TSP1 (1:300; all Abcam, UK) and then incubated with secondary antibody for 2 hours at room temperature: Alexa Fluor 594 goat anti-rabbit (1:300), fluorescein isothiocyanate (FITC) goat anti-rabbit (1:300), FITC goat anti-mouse (1:300), or Alexa Fluor 594 goat anti-mouse (1:300; all Invitrogen, CA). Sections were also stained with 4′,6-diamidino-2-phenylindole (Beyotime, Beijing) for 15 min. Stained samples were visualized, and images were captured under a confocal microscope.