A somewhat common event in movies, television, and even some video games is a character pulling out a pair of paddles to shock someone back to life. While the media may not represent defibrillators very accurately, the devices do save lives by shocking hearts into a better rhythm. These shocks can be damaging to the body though, and are certainly painful, so researchers at Johns Hopkins University are looking into replacing them with light pulses.
For about a decade now, researchers have been developing the field of optogenetics, which involves inserting light-responsive proteins into living cells. These proteins, called opsins, allow streams of ions, which carry an electrical charge, to pass through their host cell when exposed to light. As the field is still young, and thus needs more study, the Johns Hopkins researchers have only be testing it on virtual hearts.
If this technology does eventually make it into defibrillators and pacemakers, we would see these devices being less harmful to the bodies they are implanted in, and they would be more efficient than their electrical counterparts. The researchers estimate that we could see such light-based devices within a decade.
Source: Johns Hopkins University