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Tortoise Inspires Development of Tiny, Insulin-Injecting Robotic Capsule
Scientists may have found a way to deliver insulin and other drugs by ingestible capsule rather than injection. Taking their cue from the leopard tortoise, which always rights itself after rolling over, they developed Soma, which is shaped like the tortoise’s shell. Inside the device, a miniature post made of insulin pops out and injects the drug after the device positions itself against the stomach wall. Soma then travels through the colon and is eventually passed by the patient.
The researchers knew that if they could get a drug through the wall of the stomach, the medicine would enter the bloodstream. As the stomach has few pain receptors, a tiny prick would not even be felt. But they had to make a device that would land in a predictable way.
By imitating the leopard tortoise’s angled shell, which enables the creature to roll back onto its feet however it may fall, the scientists produced a tiny device that would always land on the stomach’s wall, the right way up.
The insulin needle was compressed and held in place with a thin disc of sugar. Controlling the disc’s size enabled the researchers to control how long the mechanism would stay intact. They decided on five minutes. When the sugar dissolves in the moist conditions of the stomach, the insulin post pops out.
Currently, a patient swallows a capsule containing the device. After ten minutes, the capsule dissolves and the device lands on the stomach wall. Five minutes later, the sugar disc dissolves, releasing the post. It pokes through the stomach wall and delivers the insulin to the bloodstream. Eventually, the device is excreted.
In tests with pigs and rats, Soma delivered as much insulin as conventional injections. But the stomach had to be empty when the animals swallowed the capsules. The researchers hope to begin testing the device in humans in three years.
Source: New York Times, February 11, 2019