Source: University of Sydney

“Medical implants are constantly under pressure to perform in the human body. A heart valve is constantly under high pressure to pump blood, opening and closing half a billion times over 10 years,” the team noted. “The current average lifespan of existing heart valve implants is less than 10 years and there is always a risk of them degrading or complications occurring. By using Zwitterion coated materials, we aim to decrease the risk of blood clots and increase the lifespan of heart valves and other medical implants,” the researchers explained.

Zwitterions — which are molecules featuring both positively and negatively charged groups that result in a neutral overall charge — successfully form bonds with water molecules, and are present in human cells as part of the cell membrane. There, they form a thin layer of water and ensure that blood and other proteins navigate through the heart and other organs without adhering to other surfaces.

Inspired by this, the researchers sought to extend the lifespan of medical implants with their zwitterionic coating, which was applied to material in a layer just a few nanometers thick and that successfully formed a layer and bubble of water. Conversely, on material without the coating, water was repelled and spread beyond the material’s boundaries.

The researchers are now investigating new formulations that are capable of being chemically attached to the surface of any type of implant — composed of tissues, metals or plastics/rubbers — with the intention of lessening their interactions with blood.

Going forward, the team intends to explore the number of Zwitterions required, the ideal coating thickness and concentration used as well as the ideal method for anchoring Zwitterions to the surface of a material.