Ultrasound preexposure improves endothelial cell binding and retention on biomaterial surfaces

In spite of the extensive studies regarding the effects of ultrasound on biological systems, the influence of low-intensity ultrasound on endothelial cells has rarely been investigated. In this work, the effect of ultrasound in improving the binding between endothelial cells and biomaterial substrates was evaluated. Based on the results, low-intensity ultrasound could change the morphology and matrix secretion of endothelial cells, and such effects persisted when preexposed cells were seeded to another substrate. The cells preexposed to ultrasound were spread further on the substrate. The actin stress fibers of ultrasound-preexposed cells on RGD-modified surfaces were especially intense and well oriented. Ultrasound could probably activate cellular integrins and subsequently allow RGD to bind them. A much firmer adhesion of ultrasound-preexposed endothelial cells to the biomaterial surface coated with the RGD-containing protein was demonstrated. Finally, polyurethane small-diameter vascular grafts seeded with ultrasound-preexposed endothelial cells showed enhanced cell retention on graft surfaces upon flushing.