The astonishing micro-robots you swallow that spot cancer and might help treat it

This is Everyday Science with Clare Wilson, a subscriber-only newsletter from The i Paper. If you’d like to get this direct to your inbox every week, you can sign up here. One of my favourite sci-fi films as a child was the 1966 Raquel Welch movie, Fantastic Voyage, about a miniaturised submarine complete with crew, who zoomed through a patient’s bloodstream to destroy a life-threatening blood clot. While human shrinking is not on the table, the development of miniature medical robots could yield such huge benefits it is being seriously pursued by research groups around the world. This month, a team in Beijing revealed a medical micro-robot for delivering drugs to precise locations in the gut. Other groups are building devices for destroying tumours, widening arteries – and dissolving blood clots, a common cause of strokes. Shorts While more advanced devices small enough to get through blood vessels are probably at least a decade away from being used on patients, NHS doctors are already deploying a more basic kind of medical micro-robot in the form of a swallowable capsule containing a tiny camera. The micro-robots already helping to spot cancer Used to investigate gut problems such as bleeding or pain, the capsules are an alternative to the original approach of pushing a camera on the end of a long thin tube either down the throat or up the bottom, called endoscopy. A camera on a tube has the advantage that it can be manoeuvred to take a closer look at any suspicious areas. The first generation of camera capsules, by contrast, just move along at the gut’s natural pace, usually exiting into the toilet within a few days. A high-tech medical capsule used by doctors to investigate gut issues (Photo: Aflo Images) But more advanced camera capsules can now be manoeuvred, at least within the stomach, using a magnetic steering system. They are used to investigate possible symptoms of stomach ulcers, growths and cancer. With one such system, called NaviCam, the patient fills their stomach with a large drink of water, then lies on a platform surrounded by magnetic controls. The doctor steers around the tiny device using two joysticks, while watching the camera’s view on a screen, to inspect all of the stomach’s interior. ‘We can put the drug right where we want it’ Magnets have turned out to be the best way to steer many other kinds of medical micro-robots that are at earlier stages of development. Beijing researchers have developed a smaller device they call a “spiny milli-ball robot”, which is 6.5 mm in diameter, and is designed for drug delivery. At this smaller scale, this robot can be steered around within the more confined space within the lower bowels, not just in the stomach. The spikey ball goes inside a small capsule for ease of swallowing, which dissolves in the stomach. Once the device reaches the right place in the gut, the spikes mean the device can be magnetically pulled into the gut tissue, when it releases its drug payload. As a test, the device was successfully used to deliver the drug insulin to the lower intestine of pigs, the Beijing researchers reported this month, in the journal Cyborg and Bionic Systems. Precision drug delivery would be useful in a wide range of diseases, says Professor Bradley Nelson, a roboticist at Swiss university ETH Zürich, who was not involved in the Beijing research. About a third of experimental drugs fail in clinical trials because, although they work at treating the disease, they are too toxic, he says. But releasing drugs at just the right spot in the body slashes the dose that is needed to be effective, sometimes by a factor of several hundred, thus, solving the toxicity problem. “We can put the drug right where we want it – that’s the promise of delivering drugs with micro-robots,” says Nelson. Dissolving blood clots and treating cancer Micro-robots have to shrink further still if they are ever to rove through the bloodstream, but that’s what Nelson’s team has achieved. Last year, they showed that their 2-mm-wide micro-robot can be magnetically guided around a pig’s bloodstream. The surgeon could see the blood vessels, as an X-ray of the “patient” was being carried out at the same time, with the metallic robot standing out clearly on the screen. A PlayStation controller is used for steering. “It’s like playing a video game,” says Nelson. The 2mm-wide micro-robot being developed by ETH Zurich to travel through blood vessels (Photo: Luca Andrea Donati) In a separate test using a silicone model of the brain’s circulatory system, the robot delivered a powerful drug that dissolved a blood clot. It could also potentially be used to treat cancerous tumours or localised infections. Nelson says the more he talks to surgeons, the more he discovers new potential applications of the micro-robots – the latest being to act as a physical block of the blood supply to aneurysms, weak spots in blood vessels that can burst. The potential cancer game-changer When micro-robots get smaller still, they can be used in swarms so they can deliver enough of any medication, says Dr Ali Kafash Hoshiar, a roboticist at the University of Essex. His group has developed drug-containing devices as small as one-tenth of a millimetre, and even smaller magnetic specks, which are so simple in structure they are more like metallic particles than micro-robots. These swarms of particles can still do something medically useful, though. If they are steered to surround a cancer, they can be made to heat up, by changing the magnetic field, and destroy the tumour. He has shown this works in mice. While the swarm approach is quite different to Raquel Welch’s miniature submarine, Hoshia says he was inspired by watching that film as a child. When micro-robots arrive they will make current forms of medicine and surgery look crude by comparison, he says. “Fantastic Voyage is the dream.” I’ve also written Alzheimer’s disease gets so much attention it can overshadow vascular dementia, the second most common cause of memory loss in later life. A new view says that vascular dementia is more common than we think, but there are ways to stop it. I’ve been reading Shrines of Gaiety is a change of scene for the celebrated novelist Kate Atkinson. Set in seedy 1920s London, it follows the fortunes of a hardened criminal matriarch, a police detective on the case and a provincial librarian who stumbles into their crossfire. The characters are portrayed with engaging detail and pacey dialogue. It is also a masterful depiction of London society leaning into hedonism as it recovers from the First World War. Atkinson has triumphed again.