Your spit could fuel a generator in the near future

Saliva-powered micro-sized microbial fuel cells could produce minute amounts of energy sufficient to run on-chip applications.

Bruce E. Logan, Evan Pugh Professor and Kappe Professor of Environmental Engineering, Penn State, credited the idea to fellow researcher Justine E. Mink.

The researchers said that by producing nearly 1 microwatt in power, this saliva-powered, micro-sized MFC already generates enough power to be directly used as an energy harvester in microelectronic applications.

The researchers believe that the emergence of ultra-low-power chip-level biomedical electronics, devices able to operate at sub-microwatt power outputs, is becoming a reality.

One possible application would be a tiny ovulation predictor based on the conductivity of a woman's saliva, which changes five days before ovulation. The device would measure the conductivity of the saliva and then use the saliva for power to send the reading to a nearby cell phone.

The anode is actually composed of carbon nanomaterial graphene. Other microbial fuel cells used graphene oxide, but the researchers showed that pure multi-layered graphene can serve as a suitable anode material.

While the researchers tested this mini microbial fuel cell using acetate and human saliva, it can use any liquid with sufficient organic material.

The study has been published in Nature Publishing Group's Asia Materials.