It began with a theory -- scientists at the University of California knew graphene could convert light into electricity, and wondered whether that electricity had the capacity to stimulate human cells. Graphene is extremely sensitive to light (1,000 times more than traditional digital cameras and smartphones) and after experimenting with different light intensities, Alex Savchenko and his team discovered that cells could indeed be stimulated via optical graphene stimulation."
I was looking at the microscope's computer screen and I'm turning the knob for light intensity and I see the cells start beating faster," he said. "I showed that to our grad students and they were yelling and jumping and asking if they could turn the knob. We had never seen this possibility of controlling cell contraction."
The source paper can be found here, and it is open-access.
Again, this is why it is vital that funding in basic physics continues at a healthy pace. Even if you do not see the immediate application or benefit from many of these seemingly esoteric research, you just never know when any of the discovery and knowledge that are gained from such areas will turn into something that could save people's lives. We have seen such examples NUMEROUS times throughout history. Unfortunately, people are often ignorant at the origin of many of the benefits that they now take for granted.