"If we're going to be making more cars, more robots, more clothes, more food, we're going to need more water. And if we're doing that, we're going to generate more wastewater. If we don't solve this problem, there's going to be a bottleneck."

"To treat an infection, doctors have to find and diagnose it first. But a new approach involving what researchers are calling "living materials" could fundamentally change that. Designed to sit inside your body and activate when needed to help fight infections at the source, the strategy could dispense with the need for pills, shots and even diagnostics.

In a new study published in Science on Thursday, researchers describe successfully implanting a mouse with a "living material" made with genetically engineered bacteria to treat an infection. The technology, if validated in humans, could be used to help prevent infection in surgeries or as a long-term therapeutic that automatically responds to pathogens.

"Living" medicine isn't totally new. Scientists already knew that bacteria can be programmed to sense pathogens and self-destruct when they do so, releasing drugs to kill the invader.

But researchers have been wary about such approaches. "One of the big concerns that everyone has is that we're injecting live bacteria into our body," says Tetsuhiro Harimoto, the study's lead author and a postdoctoral fellow at Harvard University. "We don't want them to disseminate and cause infections."

To solve the problem, Harimoto and his colleagues built a "hydrogel," or jellylike, container. It's permeable like a mesh yet stiff enough to contain a live and growing population of bacteria without bursting open and strong enough to withstand some wear and tear."