Healthcare (Commonwealth Union) – Zwitterions which are a common macromolecule present in human cells. Researchers at the University of Sydney are now exploring how Zwitterions can be used to develop materials that help prevent blood clots in medical implants and devices.
With an estimated 500,000 to 600,000 Australians affected by heart valve disease in 2021, medical implants such as heart valves and stents are vital for saving lives. However, blood proteins can adhere to the surfaces of these implants, accumulating over time and leading to clot formation, which often necessitates invasive surgery for removal or replacement.
Blood clots have always been a serious concern for healthcare professionals. The device known as SOLITAIRE, showed promise in removing blood clots from blocked brain arteries over a decade ago and gave patients hope for effective treatments.
Dr. Sina Naficy, who leads a research team focused on developing heart valves that are more resistant to clot formation indicated that medical implants must endure constant stress within the human body. A heart valve, for example, operates under intense pressure, pumping blood and opening and closing approximately half a billion times over a decade.
Dr. Naficy and his team focused on the unique properties of Zwitterions—chemically neutral yet highly attracted to water.
Much like other scientific breakthroughs inspired by nature, the researchers drew inspiration from the cell membrane and are working to replicate its functions. Their goal is to develop materials that can enhance the durability and longevity of medical implants.
The team has successfully engineered a zwitterionic coating that, when applied in ultra-thin layers just a few nanometers thick, forms a protective barrier of water—acting like a liquid shield. In contrast, uncoated surfaces repel water, causing it to spread beyond the material’s boundaries.
Dr. Sepehr Talebian from the School of Chemical and Biomedical Engineering stated that they are actively developing new formulations that can chemically bond to a wide range of implant surfaces, whether they are made of tissue, metal, plastic, or rubber, with the ultimate goal of minimizing their interaction with blood.
“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,” explained Dr Naficy, from the University’s School of Chemical and Biomedical Engineering, Faculty of Engineering. Dr Naficy is also a member of The University of Sydney Nano Institute.
Researchers of the study pointed out that the world is teeming with molecules that carry positive and negative charges, and their interactions form the foundation of life’s chemistry. Among these, zwitterions stand out as extraordinary molecules because they possess both positive and negative charges simultaneously, rendering them electrically neutral. The term “zwitter” captures this unique characteristic—it means “hybrid” in German. Additionally, zwitterions have a remarkable ability to bond effectively with water molecules.
Zwitterions are naturally present in our cells, particularly as components of cell membranes. They play a crucial role by forming a thin layer of water, which ensures that blood and other proteins can flow smoothly through the heart and other organs without adhering to surfaces. This property is vital for maintaining proper biological function.
One of the biggest challenges researchers are trying to solve is determining the optimal number of Zwitterions needed—striking the perfect balance.
The team recently published a comprehensive review in Cell Biomaterials, outlining the potential applications of Zwitterions in biomedicine and offering a detailed guide for developing surface coating technologies.
explained Dr. Talebian indicated that there is significant promise, but how do they best apply Zwitterions? What is the ideal coating thickness? What concentration should be used? They cannot simply immerse an artificial heart valve in a Zwitterionic solution without first identifying the optimal conditions. Too much could worsen clotting, while too little may not prevent it effectively.
