MIT technology can see microbes from 90 meters away

Summary

Nature has evolved a stunning array of biosensors for detecting the physical world.A single E. coli cell, for example, can precisely sense chemical gradients and “swim” toward or away from them. Some bird species, including robins and warblers, can see magnetic fields using cryptochrome proteins embedded in their eyes to guide them during their annual migration. Bogong moths use photons from distant stars as a compass while soaring 1,000 kilometers across southeast Australia. In other words, organisms can sense not only tastes and smells, but also individual molecules, magnetic fields, and infrared or ultraviolet light.Humans have long used other creatures’ senses to aid and extend our own, too. As far back as 1,000 BCE, humans employed pigeons to carry messages across cities and kingdoms, taking advantage of their remarkable homing instinct. Dogs’ superior sense of smell is often used to sniff out disease, truffles, contraband, and explosives. And today, the city of Poznań, in Poland, uses just eight mussels to monitor their water quality.But increasingly, over the last quarter century, scientists have not only used entire organisms to sense the natural world, but have also taken particular genes from those organisms and adapted them into molecular biosensors. Just as a smoke detector has a sensor that detects particles in the air and a buzzer that then alerts us, all human-made biosensors have two basic components.One of the mussels used to monitor Poznań’s water supply. Credit: Julia PelkaThe first is the sensor itself — an enzyme, antibody, or engineered cell — that physically recognizes a target, whether a pollutant, virus, or rise in temperature. The second is the transducer, which converts that recognition event into a signal we can perceive, such as a glowing light.Although bioengineers have adapted hundreds of biosensors from nature, they have been less successful in making better transducers. Nearly every biosensor today still relies on a narrow set of out...