It is swallowed with a glass of water and, once in our bowels, the pill diagnoses any gastrointestinal problems, and sends the report to the phone. It is a futuristic scenario that could soon become reality thanks to a prototype developed by researchers at MIT in Boston.

Hallucinatory journey. It is not the first model of a system designed to travel in the body and diagnose from inside - in a painless way and without tubes or scars - what happens in the bowels. The camera capsules that make an endoscopy of the gastro-intestinal tract have been a reality for some years now.

However, MIT researchers have come up with a device that goes further, allowing them to explore the physiology of the most inaccessible parts of the intestine, but also to diagnose disorders or disease trends. Their idea combines biology and electronics .

Bacteria & chips. The model, called IMBED, for Ingestible Micro-Bio-Electronic Device, is in fact made up of bacterial cells placed on a sensor, covered by a semipermeable membrane that allows the molecules of the surrounding environment to penetrate and spread inside. The bacteria have been modified with genetic engineering in order to emit a light signal when they detect the presence of a certain molecule. At that point a transistor measures the amount of light emitted and transmits the information to a microprocessor, which in turn sends a wireless signal to a computer or a smartphone. Everything is contained in a structure just larger than an antibiotic tablet.

Successful experiment. In a study on pigs, published in Science, the researchers obtained proof of principle that it can work. In this case, a strain of Escherichia coli bacteria has been engineered to emit light when it picks up a component (heme) of the hemoglobin contained in red blood cells and a sign of hemorrhage. Within two hours, the pill diagnosed without error the presence of blood that had been injected into the animals' stomach.

Diagnosis for the future. In this case, it is a demonstration of principle, because haemorrhages, for example gastric ones due to an ulcer, are already usually readily recognized today. But the useful applications in clinical practice could be many others. The bacteria that act as sensors, according to the researchers, could be engineered to monitor inflammatory molecules and thus the course of intestinal diseases such as Crohn's disease, or infections or even tumors of the stomach and intestines.