New Material Developed for Vascular Graft

A new material, intended for use in vascular grafts, could help patients with damaged arteries regenerate new ones when undergoing coronary artery graft surgery.

The new material, developed by scientists at Virginia Commonwealth University (VCU, Richmond, USA), is a blend of polydioxanone (PDO), a synthetic biodegradable polymer that has been used in suture materials for years, and elastin fibers, used to enhance elasticity and bioactivity of the graft. Elastin, a natural polymer, is also a major component of the arterial wall and is critical to the graft in providing a base for the cells to recognize and interact with the body. Using a technique known as electro-spinning, the researchers were able to manipulate the PDO-elastin composite into a conduit, or hose, for use as a small diameter vascular graft.

The fibers of the new material are fewer than 500 nm in diameter, compared with the average hair shaft, which is 80,000-100,000 nm. The PDO-elastin blend undergoes slow degradation and causes few adverse reactions compared with previous materials used for the same purpose. The composition of the new material reinforces the graft's mechanical strength, which is critical in order to resist the hydraulic forces generated by blood pressure while the regeneration process is taking place. The purpose of the new material would be to help a patient to generate a new artery, and if it works as designed, the researchers hope that at six months post-surgery there would be no more synthetic structure left.

"Regeneration needs to be timed just right, and the cells' regrowth needs to be strong enough so that the patient's own artery can take over for the synthetic material and promote regeneration,” said lead author Gary Bowlin, Ph.D., the Harris professor of biomedical engineering at the VCU School of Engineering. "Additionally, the synthetic material must degrade, because any foreign material in the body for an extended time is susceptible to inflammatory response or even severe infection such as staphylococcus.”



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