A spoonful of robots: miniature medical devices go inside the human body

When a doctor wants to perform an endoscopy on a patient to check for signs of stomach cancer, there’s a very small risk they could perforate the lining of the oesophagus. And, while the procedure is usually pain-free, the patient might feel some discomfort.In the future, patients may no longer need to have a tube fed down their throat into their stomach. Instead they could simply swallow an ingestible device in the form of a pill. Engineers at Massachusetts Institute of Technology (MIT) have invented exactly this. It’s made from a jelly-like substance: a combination of water and polymers. Inspired by the pufferfish, the team of researchers realised that in order for any edible pill to remain in the stomach once it has passed down the oesophagus, and not then pass out through the pylorus, it needed to be inflated. To achieve this, the team experimented with various solutions, eventually settling on an inner material that contains sodium polyacrylate, which is known for its ability to soak up liquids and inflate. The super-absorbent polymer has numerous commercial uses, including in female hygiene products.