Heart patients may in future be injected with microscopic drug-releasing particles that cling to the inside walls of diseased arteries.

Scientists in the US have successfully tested the so-called “nanoburrs” in rats.

The particles consist of spheres just 60 nanometres across, more than 100 times smaller than a red blood cell.

Each one is coated with tiny protein fragments that allow it to stick to the broken surface of damaged artery walls.

At its core the particle has a drug designed to combat narrowing of blood vessels bound to a chain-like polymer molecule.

Over a period of days the drug is slowly released and gets to work treating the artery. The time it takes for the drug to be released is controlled by varying the length of the polymer. Nanoburrs could be employed alongside vascular stents, standard care implants that prop open obstructed arteries, say the researchers.

They could also provide an alternative treatment when it is difficult to use a stent, such as near a fork in an artery.

The same team has previously developed nanoparticles to seek out and destroy cancer tumours.