Tiny ‘living robots’ made from FROG embryos could be used to destroy cancer cells
Tiny ‘Living robots’ named Xenobots have been created from frog embryos and they could be used to destroy cancer cells or remove microplastics from the oceans.
They were developed by researchers from Vermont University and Tufts University who adapted stem cells taken from the embryo of the African frog Xenopus Laevis.
The bots are just a 25th of an inch wide (1mm) and can be programmed to perform a range of tasks including delivering medicine directly to a point in the body.
Researchers say the new ‘artificial cells’ can be shaped in any way necessary for the task at hand and are ‘indestructible’ and able to self repair.
They were developed by researchers from Vermont University and Tufts University who adapted stem cells taken from the embryo of the African frog Xenopus Laevis
‘They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact – a living, programmable organism’, said study author Joshua Bongard.
Tests showed groups of them would move around in circles, pushing pellets into a central location – spontaneously and collectively.
Others were built with a hole through the centre to reduce drag.
In simulated versions, before the first bots were actually created, the scientists were able to make this hole into a pouch – to carry an object.
‘It’s a step toward using computer-designed organisms for intelligent drug delivery’, according to Professor Bongard.
The 1966 cult classic Fantastic Voyage starring Raquel Welch featured a vehicle that was shrunk down to enter the body of a scientist and cure a brain tumour
The idea of using a ‘tiny machine’ to deliver medicine to exactly the right point in the human body is a common trope in science fiction.
The most famous example is the cult 1966 film Fantastic Voyage starring Raquel Welch – in the movie a vehicle was shrunk to microscopic size and injected into a scientist to cure a brain tumour.
‘These xenobots are fully biodegradable – when they’re done with their job after seven days, they’re just dead skin cells’, said Professor Bongard.
‘We sliced the robot almost in half and it stitches itself back up and keeps going. This is something you can’t do with typical machines.’
The breakthrough has wide implications for medicine where these machines could travel around the bloodstream – destroying harmful bodies, such as cancer cells.
Professor Michael Levin, a biologist at Tufts University, said: ‘We can imagine many useful applications of these living robots that other machines can’t do.
‘These include searching out nasty compounds or radioactive contamination, gathering microplastic in the oceans or travelling in arteries to scrape out plaque.’
Lead author Sam Kriegman, a doctoral student at Vermont, used an evolutionary algorithm to create thousands of candidate designs.
After a hundred independent runs the most promising were selected for testing – based on what skin and cardiac cells can do.
Tests showed groups of them would move around in circles, pushing pellets into a central location – spontaneously and collectively
Stem cells – that can turn into any tissue or organ – were then harvested from the embryos of the frogs and left to incubate.
Then – with tiny forceps and an even smaller electrode – microsurgeon Dr Douglas Blackiston cut and joined the single cells under a microscope into the shapes specified by the computer.
Assembled into body forms never seen in nature, the cells began to work together.
‘It’s 100 per cent frog DNA – but these are not frogs’, said Professor Bongard.
After a hundred independent runs the most promising were selected for testing – based on what skin and cardiac cells can do
The skin cells formed a more passive architecture while the once-random contractions of heart muscle cells became an ordered forward motion as guided by the design – enabling the robots to move on their own.
These reconfigurable organisms were shown to be able move in a coherent fashion – and explore their watery environment for days or weeks.
They were powered by embryonic energy stores, the researchers said.
‘As we’ve shown, these frog cells can be coaxed to make interesting living forms that are completely different from what their default anatomy would be’, said Bongard.