ETH Zurich researchers have developed a gene switch that can be operated with the green LED light emitted by commercial smartwatches. This revolutionary approach could be used to treat diabetes in the future.   With the green light of a smartwatch, researchers can switch on an insulin-​producing gene network. (Photograph: Colourbox)   Many modern fitness trackers and smartwatches feature integrated LEDs. The green light emitted, whether continuous or pulsed, penetrates the skin and can be used to measure the wearer’s heart rate during physical activ...