Controlling insulin formation with the smartwatch

Many modern sports watches or smartwatches have integrated LED diodes. These emit continuous or pulsed green light that penetrates the skin and is used, among other things, to measure the pulse during exercise or at rest.

Such clocks are now in widespread use. That's why ETH researchers led by Martin Fussenegger from the Department of Biosystems in Basel want to use this light source to control genes through the skin and change the behavior of cells. The difficulty here is that "a molecular system that reacts to green light does not exist naturally in human cells," Fussenegger emphasizes, "so we had to construct something new."

Green light of the clock activated gene

The ETH professor and his colleagues finally developed a molecular switch that - once implanted - can be activated with green light from smartwatches.

The switch is coupled to a genetic network that the researchers added to human cells. For this prototype, they used HEK cells as usual. Depending on the configuration of this network - in other words, which genes it is equipped with - it can produce insulin, for example, as soon as green light hits the cells. If the light is switched off, the switch is inactivated and the process stops.

Standard software used

The researchers used the smartwatch's standard software for this and did not even have to develop their own programs. In their experiments, they were able to turn on the green light by starting the "running app." "Such off-the-shelf watches can be used universally to flip the molecular switch," Fussenegger says. New models send the light in pulsed mode, which is even better for keeping the gene network running.

The molecular switch, however, is more complicated. A molecular complex has been incorporated into the membrane of HEK cells that is coupled to a corresponding counterpart, similar to a railroad car coupler. As soon as the green light is switched on, the piece projecting into the cell interior detaches and is transported into the cell nucleus. There it switches on a gene that produces insulin. As soon as the green light goes out, the detached part reconnects with the counterpart anchored in the membrane.

Control implant with wearables

The researchers tested their system both on a bacon rind and on living mice, in which they implanted the appropriate cells and strapped on a smartwatch like a backpack. By starting the watch's running program, the researchers turned on the green light and set the cascade in motion.

"This is the first time that commercially available smart electronic devices worn on the surface of the skin, so-called wearables, can be used to control such an implant," the ETH professor points out. Most watches have a green light, so it makes sense to gear a potential future application toward that. That way, users would not have to buy a special device.

However, it would take at least 10 years for the technology to reach the clinic, Fussenegger estimates. The cells used in this prototype would have to be replaced by the user's own cells; the system would also have to get through the clinical phases before being approved. The hurdles for this are high: "To date, there are very few approved cell therapies," Fussenegger emphasizes.

Source: ETH News