Could we use the flow of blood in our veins to generate electricity?

Could we use the flow of blood in our veins to generate electricity?
 

 Humans have been harnessing the power of flowing water for many years: the first water wheels had appeared in Egypt as far back as the 4th century BC, and in the modern era 16% of the world’s electricity production is down to hydroelectric power (thanks mainly to huge projects like the Three Gorges Dam in China.) But now an intriguing new application of carbon nanotubes may allow us to generate power from the flow of a different liquid — human blood. 
 
 A research team from Fudan University in China have developed a type of fibre, less than 1mm thick, that can generate electricity when it’s surrounded by saline solution — such as water in a thin tube, or even human blood in a blood vessel. They detail the findings in a paper, A One-Dimensional Fluidic Nanogenerator with a High Power Conversion Efficiency, published in the journal Angewandte Chemie in August. 
 
 The fibre operates in an interesting way. Carbon nanotubes are electroactive, which means that they change shape in the presence of an electrical field. When the fibre is placed in a flowing saline solution, such as water or blood, the relative movement between the solution and the fibre creates a potential difference (voltage) across the fibre: it changes the charge distribution on the nanotube, which can be used to drive a current. The power conversion efficiency when operating at its best was 22.3% for the device: high compared to many nanogenerators. 
 
 It’s unlikely that you’ll be able to plug your smartphone into a USB port on your body and power it merely using the blood-flow any time soon — not that you’d want to, as the idea of vampiric electricity sounds just a little bit terrifying. This technology could be useful, however, for medical applications — if the fibres could be used to power nanobots in the blood, for example, it might make such treatments more feasible in the future. Due to the flexibility of carbon nanotubes, which can be woven into fabrics, this may also allow wearable tech to recharge itself, if the efficiency could be improved.

This story originally appeared on pionic.org.