Tiny robot armies guided to the brain by magnets ‘could treat condition that causes 500,000 deaths every year’

TINY robots that can be injected into the human body could help manage bleeds in the brain, scientists say.

The nanoscale machines are remotely controlled to carry out complex tasks - such as targeted drug delivery and organ repair - in a minimally invasive way.

The development could "open new frontiers in medicine", experts hope.

In a study co-led by the University of Edinburgh's School of Engineering, researchers showed the robots could be used to treat bleeds in the brain triggered by aneurysms, which cause about 500,000 deaths globally each year.

An aneurysm is a blood-filled bulge on a brain artery that can rupture and cause fatal bleeds, and lead to stroke and disability.

In lab tests using model aneurysms and rabbits, the team engineered magnetic nanobots about a 20th the size of a human red blood cell.

These were made up of blood-clotting drugs encased in a coating designed to melt at precise temperatures.

Scientists injected several hundred billion of the bots into an artery, and then remotely guided them as a swarm to the site of the aneurysm using magnets and medical imaging.

Once the army of tiny bots was in position, researchers used magnets to cluster them together inside the aneurysm and heat them to their coatings' melting point.

This released the drug at the precise spot where it could prevent or stem bleeding into the brain.

Dr Qi Zhou, from the University of Edinburgh's School of Engineering, who co-led the study, said: "Nanorobots are set to open new frontiers in medicine, potentially allowing us to carry out surgical repairs with fewer risks than conventional treatments and target drugs with pinpoint accuracy in hard-to-reach parts of the body.

"Our study is an important step towards bringing these technologies closer to treating critical medical conditions in a clinical setting."

Researchers said the study showed nanobots had the potential to transport drugs to precise locations without risk of leaking into the bloodstream, which they said was a key test of the technology's safety and efficiency.

"The study could pave the way for further developments towards trials in people," Dr Zhou added.

The team also said the nanobots could reduce the need for implants in the treatment of brain aneurysms, such as coils or stents (mesh tubes).

Typically, doctors thread a tiny microcatheter tube along blood vessels before using it to insert metal coils to stem the aneurysm blood flow, or a stent to divert the bloodstream in the artery.

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Using their new technique would reportedly reduce the risk of implants being rejected by the body, and curb reliance on anti-blood-clotting drugs, which can cause bleeding and stomach problems.

The method also avoids the need for doctors to manually shape a microcatheter to navigate a complex network of small blood vessels in the brain to reach the aneurysm – a painstaking task which may take hours during surgery, the researchers said.  

Larger brain aneurysms – which can be difficult to stem quickly and safely using metal coils or stents – could potentially be treated using the new technique too, they added.

The study, published in the nanoscience and nanotechnology journal Small, was led by a team from the UK and China.

The same researchers have also developed nanorobots to remove blood clots, which they said also showed their potential in the treatment of strokes.