Scientists have carried out trials using microscopic drones that could be used to seek and repair damaged arteries, preventing heart attacks and strokes. 

Researchers have completed the first successful tests of nanoparticles – which are targeted to go where they are needed – in mice, and hope to soon to conduct the first patient trials.

The nanoparticles are designed to latch on to hard plaques in the arteries, made from fat cholesterol and calcium, which cause heart disease. 

Once they reach their target, the "drones" release a drug derived from a natural protein that repairs inflammation damage in the body.

Each of the tiny particles, made from a plastic-like material, is 1,000 times smaller than the tip of a human hair.