Scientists at the Research Laboratory of Matsushita Electric developed a device that produces electricity from glucose contained in the blood.
The process of energy production in something like metabolism, electrons are generated by oxidation of glucose by the enzymes. In theory, the blood could be worked out, and 100 watts, enough to light bulbs, but it had to be developed into electricity everything a person eats.
While the Japanese were able to get blood out of a modest amount of electricity, but less energy than light devices, such as small robots, biological nanogenerator quite amiss. Ultimately, the lab Matsushita, using the energy of blood, hoping to create a more or less efficient "human batteries".