Researchers at McMaster University in Canada have engineered ‘smart surfaces’ with coatings claimed to be able to repel almost everything they are expected to encounter, including bacteria, viruses and living cells.

The surfaces can also be modified for targeted beneficial exceptions. This feature makes it possible for implants such as vascular grafts, replacement heart valves and artificial joints to bond to the body without leading to potential infection or blood clotting.

Researchers said the new nanotechnology possesses the potential to significantly minimise false positives and negatives in medical tests by removing non-target element interference in blood and urine.

Though completely repellent surfaces have been available since 2011 for waterproofing goods, they demonstrated limited medical application.

“A coating that repels blood cells could potentially eliminate the need for medicines such as warfarin that are used after implants to cut the risk of clots.”

McMaster University School of Biomedical Engineering researcher Tohid DIdar said: “It was a huge achievement to have completely repellent surfaces, but to maximise the benefits of such surfaces, we needed to create a selective door that would allow beneficial elements to bond with those surfaces.”

Citing an example, the researchers noted that a repellent coating on a synthetic heart valve can prevent sticking of blood cells and formation of clots, making the implant safe.

Since a completely repellent coating can also prevent integration of the valve into the body tissue, the researchers designed the new surface to allow adhesion with only heart tissue cells.

The same approach can be applied to other medical implants.

McMaster University Biomedical Engineering student Sara Imani said: “A coating that repels blood cells could potentially eliminate the need for medicines such as warfarin that are used after implants to cut the risk of clots.”

The team further expects selectively designed repellent surfaces to facilitate more accurate results in diagnostic tests. This will be made possible by enabling only the test target to stick to the biosensor.

Findings from the research were published in the ACS Nano journal. Currently, the researchers are working to advance the research into clinical use.