Endothelial cell retention, under physiologically relevant shear flow, is not affected by CD47 immobilization. (A) Representative fluorescent micrographs of HUVECs cultured on thiolated pepCD47, recCD47, BSA-modified and unmodified stainless steel surfaces. Once confluent, the HUVECs were exposed to 25 dynes/cm2 fluid shear stress (FSS) for 4 hr using the FlexCell® Streamer® device. Following shear stress exposure, the HUVECs were fixed and permeabilized. Actin stress fibers were then stained with rhodamine-Phalloidin, following which the nuclei were DAPI stained. (B) DAPI positive cells from nine random fields were counted and compared with cell counts from cultured HUVECs grown on the various surface, but not exposed to FSS. Graph shows percent retention for each surface tested.