Here’s a sentence that’s straight out of the future: Microscopic stealth drones could be repairing your damaged arteries very soon.

That’s right. Scientists are developing tiny man-made particles that can whizz around in your blood fixing the damage that causes heart attacks and strokes. Read on, because it only gets more amazing.

What are these particles?

Each tiny nanoparticle is made from plastic, and is 1,000 times smaller than the tip of a human hair.

The nanoparticles are made from a biodegradable polymer that dissolves away in the body over time and is already used in a number of approved medical products.

How do they repair artery damage?

The nanoparticles were engineered to carry pieces of an “inflammatory-resolving” protein called annexin A1, which the body uses to quell inflammation and trigger healing.

They are designed to latch onto atherosclerotic plaques – hard deposits made from accumulated fat, cholesterol and calcium that build up on the walls of arteries and can often rupture, producing dangerous clots.

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

Have tests been successful so far?

Scientists have carried out successful tests of the nanoparticles in mice and hope soon to conduct the first patient trials.

In the tests, artery damage in laboratory mice was significantly repaired after five weeks of treatment and plaques were stabilised, making it less likely for fragments to break off and clog blood vessels.

In mice injected with the nanoparticles, significant improvements were seen, including reduced inflammation and a thickening of collagen layers in atherosclerotic plaques that prevented them rupturing.

Plaques were shrunk in size, and cleared of dead cells accumulating within them.

The scientists also observed a reduction in highly destructive molecules that damage cells, known as reactive oxygen species (ROS).

Are results guaranteed?

The scientists did warn that although mice developed human-like atherosclerotic plaques, they did not suffer heart attacks. So the real test of the technology will come when it is tried out in human patients.

But because other applications of the nanoparticles have already been tested on humans, progress to clinical trials is not expected to take long.

What will happen during the human trials?

For the human trials, the team plans to fine tune the particles to optimise drug delivery and to package them with more powerful anti-inflammatory drugs.

In the trials on mice around 70% of the nanoparticles implanted themselves into the plaques and slowly unloaded their drug cargo.

Should we be excited about this?

The scientists certainly are. It goes without saying that the new treatment could have major advantages over standard procedures.

“I’m optimistic that with additional animal validation we will also consider the human testing of the inflammation-resolving targeted nanoparticles for a myriad of unmet medical needs,” said lead researcher Dr Omid Farokhzad, director of the Laboratory of Nanomedicine and Biomaterials at Brigham and Women’s Hospital in Boston, US.

“These are exciting times in medicine and the future of nanomedicine is incredibly bright.”

The results of the study appeared in the journal Science Translational Medicine.