Elasticity response of electrospun bioresorbable small-diameter vascular grafts: Towards a biomimetic mechanical response

The elasticity response of synthetic vascular grafts is very important for the grafts long term success. Natural arteries possess a characteristic response to internal pressure, known as J-curve. Mimicking this feature is believed to be the path to obtain a vascular graft that does not fail over time. In this work, two synthetic bioresorbable polymers were selected to design small-diameter vascular grafts (SDVGs) based on their biomimetic mechanical response. Poly(l-lactic acid) (PLLA) was chosen for its similar response to collagen and a segmented poly(ester urethane) (PHD) was used to introduce elastomeric properties through its elastin-like behavior. A bilayered electrospun conduit with two different PLLA/PHD blends was fabricated by mimicking the natural collagen-to-elastin ratio in the media and adventitia layers. The biomimetic mechanical response, compliance and elastic modulus were studied under pulsated pressure conditions. The grafts nanofibrous morphology as well as its layered structure resulted in properties promising for bypass applications.