Rabbit anti cd31 primary antibody

After 7 days of culture, F-actin (Life Technologies) and CD31 (PECAM-1, Abcam) stainings were performed to investigate the effective formation of endothelial monolayers within the PDMS tubes. The cells were fixed in 4% (w/v) paraformaldehyde (Sigma-Aldrich) for 15 min and incubated in 0.1% (v/v) Triton X-100 (Sigma-Aldrich) in PBS for 15 min to permeabilize the cell membrane. Afterwards, the samples were blocked in 1% (w/v) BSA in PBS for 1 h at room temperature. To label F-actin, the samples were incubated in Alexa 488-phalloidin (1:40 dilution) in phosphate buffered saline (PBS, Life Technologies). To stain CD31, the samples were incubated in rabbit anti-CD31 primary antibody (Abcam) solution (1:50 dilution) in PBS for 1 h at room temperature and then Alexa 594 conjugated anti-rabbit secondary antibody (Life Technologies) solution (1:200 dilution) in PBS for 1 h at room temperature. The samples were finally stained with 4',6-diamidino-2-phenylindole (DAPI, Life Technologies) for the nuclei. Fluorescence images were acquired using a fluorescence microscope (Axio Observer D1, Zeiss) and a laser scanning confocal microscope (TCS SP5, Leica).