Stanford bioengineer Ingmar Riedel-Kruse isn't the first person to combine biology and gaming, but he is most definitely the first to mix paramecia and Pac-Man. Riedel-Kruse has created a series of games where human players control living, single-celled organisms, manipulating the creatures' movements to collect points and avoid obstacles in a digital world.
In the presence of an electric current, these cells move, always in the same direction relative to the current. To make them play a game, all you have to do is trigger electric currents in the right places.
This isn't the same thing as just electrocuting the paramecium and watching them run. Instead, this process—called electrotaxis or galvanotaxis—is a natural part of cell behavior. In the case of lymphocytes, some researchers think galvanotaxis may be one of the triggers that helps these white blood cells move around your body and know where to go to fight intruding viruses and bacteria.
The video above will show you how Riedel-Kruse harnessed galvanotaxis for video games. And you can get a closer look at each of the four specific games at Scientific American.