Biocompatible and biodegradable TPU vessels transform into biological ones, once implanted

30-Apr-15

Polymer fabric vessels that transform into biological ones, once implanted have been developed. The artificial blood vessels are made from biocompatible and biodegradable thermoplastic polyurethanes. A team - from Vienna University of Technology and Vienna Medical University in Austria, describes how they made and tested the new material in a paper published in the journal Acta Biomaterialia. Blocked blood vessels can quickly become very dangerous - they are one of the most common causes of death in industrialized countries.It is often necessary to replace blocked blood vessels - for instance in a bypass operation - either with other vessels taken from the body or with artificial ones. Artificial blood vessels are made from biodegradable materials that gradually populate with live cells to make new tissue. As the artificial material dissolves, the new tissue takes over.However, the researchers say that the artificial materials currently available are not ideally compatible with body tissue. They note in their paper, "Current approaches often reveal limited tensile strength and therefore require thicker or reinforced graft walls." Another problem with currently available materials is they can cause the new blood vessel to become blocked, especially if it is only small in diameter. In their paper, the researchers describe how they developed a new polymer - made from thermoplastic polyurethane - with much improved mechanical properties that can be made into vessels with walls that are very similar to natural ones. The artificial vessels are made by spinning the polymer in an electrical field to form very fine threads that are then wound onto a spool. The polymer fabric is slightly porous - this allows some blood to soak into and enrich the walls with growth factors, which encourages the migration of native cells. Tests of the new artificial blood vessels in rats, showed that after 6 months there was no evidence of bulging (aneurysm), blockage (thrombosis) or inflammation.