A primary source of infection in patients receiving ventricular assist devices is part of the implanted pump itself. The implant is powered by an external battery, and the point at which a 7 mm-thick cable linking the two exits the abdomen provides an opportunity for bacterial intrusion. Replacing this relatively thick cable with a series of thinner, flexible wires that do not invite microbial occupation is the goal of researchers in Europe.

The solution focuses on the use of several copper-coated wires, each 0.2 mm or 0.4 mm wide and with irregular surfaces. According to the developers, “More flexible wires whose surface is full of microscopic craters help the skin heal,” thereby preventing infection.

The wires tested were 0.2 mm to 0.4 mm in width. Source: Nici Lebküchner/ETH Zurich

Each wire is coated in a thin layer of silicone, cooled to -20° C and placed in a condensation chamber where water droplets are pressed into the liquid silicone to form microscopic craters. When implanted in sheep, the conventional thick, flat cables caused severe inflammation while the newly designed thin, flexible cables were associated with mild inflammatory reactions. Additionally, the surrounding skin integrated better with the wires than it did with the cables.

The research conducted by scientists from ETH Zurich (Switzerland), Swiss Federal Laboratories for Material Science and Technology, COMPATH (Switzerland) and the German Heart Center Berlin is published in Biomaterials Advances.