Miniaturization is making many things possible. Miniature Biofuel Cells that produce energy from Beta-glucose in the blood can be made to power cardiac pacemakers in humans. In these BioFuel Cells, the Beta-glucose is reduced and electrons transferred to an anode. At the cathode, oxygen accepts electrons. The reaction generates electricity, water and oxidation products of glucose that are found in all cells (and easily processed). The blood contains excess of Beta-glucose so there is no shortage of supply to the fuel cell.
However, Beta-glucose is not as abundant in the blood (hemolymph) of insects. Insects use the sugar, trehalose, as the predominant blood sugar. To make the Beta-glucose Fuel Cell work with insect hemolymph (blood) a process to convert trehalose to Beta-glucose must be added.
Trehalose is a disaccharide, composed of two molecules of glucose that are chemically linked (chemical bond). The enzyme trehalase can split one molecule of trehalose into 2 molecules of alpha-glucose. Another enzyme, mutarotase can convert alpha-glucose to Beta-glucose, the fuel used in human BioFuel Cells.
A group of scientists from the Tokyo University of Agriculture and Technology, created a fuel cell designed to run on trehalose (see IEEEXplore) by adding the enzymes trehalase and mutarotase. The BFC generated power when given a trehalose solution at a concentration found in Madagascar Hissing Cockroaches. Could it generate electricity from cockroach hemolymph (blood)?
Yes. The BFC could generate electricity from cockroach hemolymph at a maximum 306 mV and 6.07 microwatts per square centimeter. The power output could be increased by increasing the oxygen available to the BFC.
What’s next? The scientists plan to develop a BFC that is less invasive to an insect for implantation. The money quote:
application of the trehalose BFC as a micro battery in novel ubiquitous robots such as cyborg insects is expected.
Look for cyborg insects containing trehalose fuel cells in the future. The BioFuel cells will be capable of powering a variety of electronic devices including chemical, sound and video sensors that can send signals to a remote receiver. The possibilities are mind boggling.