If someone is already suffering from heart failure, they certainly shouldn't have to deal with a serious infection on top of that. A new type of electrical wire, designed for powering implanted heart pumps, could help keep that from happening.
When a heart failure patient is on the waiting list for a donor heart, it's not uncommon for them to receive an implanted electric pump that keeps their existing heart beating normally until it can be replaced. That pump is powered by a connected battery, which is worn on the outside of the body.
The 7-mm-thick cable that connects the two devices runs through a hole in the patient's skin, which is a potential access point for harmful bacteria.
Making matters worse, because the surrounding skin has difficulty adhering to the cable's stiff, smooth surface, it ends up just growing downwards. The skin then acts like a funnel, guiding bacteria down into the underlying tissue.
Seeking a more biocompatible alternative, scientists from ETH Zurich and the German Heart Centre have created special thin, flexible, coated copper wires. Because the wires are less than half a millimeter wide, several of them serve the same purpose as the single cable which is currently used.
Not only does each wire go through a much smaller individual hole than is required for the cable, but because the wires are very flexible, the similarly flexible skin is better able to grow up and around them – just like it does around hairs coming up out of follicles.
Importantly, each wire is coated in a thin layer of silicone with microscopic craters on its surface. Those craters serve as attachment points for skin cells, helping the skin to regrow around the wires instead of growing downwards.
In tests performed on sheep, severe inflammation occurred at sites where traditional cables were implanted through the skin, but only mild inflammation occurred at sites where the wires were implanted. Additionally, the surrounding skin integrated better with the wires than it did with the cables.
Two papers on the study, which is being led by ETH Zurich researcher Andreas Kourouklis, were recently published in the European Biophysics Journal and Biomaterials Advances.
Source: ETH Zurich
