Nanoscale robots could manage aneurysm brain bleeds

The development could enable precise, relatively low-risk treatment of brain aneurysms, which cause around 500,000 deaths globally each year. The study is detailed in Small.

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

The study points to a future where nanobots could be remotely controlled to carry out complex tasks inside the human body – such as targeted drug delivery and organ repair – in a minimally invasive way, the researchers said.

The team, involving researchers from Edinburgh University’s School of Engineering, engineered magnetic nanorobots comprising blood-clotting drugs encased in a protective coating that are designed to melt at precise temperatures.  

In lab tests, several hundred billion such nanobots were injected into an artery and then remotely guided with magnets and medical imaging to the site of an aneurysm.  

Magnetic sources outside the body then cause the robots to cluster together inside the aneurysm and be heated to their melting point, releasing a naturally occurring blood-clotting protein, which blocks the aneurysm to prevent or stem bleeding into the brain. 

The international team, co-led by clinicians from Shanghai Sixth People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine in China, successfully tested their devices in model aneurysms in the lab and in a small number of rabbits.  

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The team said that nanorobots show potential for transporting and releasing drug molecules to precise locations in the body without risk of leaking into the bloodstream, a key test of the technology’s safety and efficacy.  

The study could lead to further developments towards trials in people.

Their advance could improve on current treatments for brain aneurysms, where doctors often thread a microcatheter 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.

The researchers said their new technique could decrease the risk that the body will reject implanted materials 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.

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. 

In a statement, Dr Qi Zhou, Edinburgh University School of Engineering and study co-lead 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.”