Glowing creatures like fireflies and jellyfish are captivating to look at but also a boon for science, as their bioluminescent molecules contribute to visualizing a host of biological processes. Now, scientists have supercharged these molecules, making them hundreds of times brighter in deep tissues and allowing for imaging of cells from outside the body. The bioengineered light source was used to track cancer cells in mice and brain-cell activity in monkeys, but its applications extend beyond the lab.
