In an article published for the Journal of the American Chemical Society, authors Michelle Ann Rasmussen, Roy Ritzmann, Irene Lee, Alan J. Pollack, and Daniel Alberto Scherson of Case Western University propose using a power supply that relies on the insect's normal feeding behaviour.
Using a real insect is much easier than starting from scratch to create a device that works like an insect, Case Western Reserve chemistry professor teamed up with graduate student Michelle Rasmussen, biology professor Roy E. Ritzmann, chemistry professor Irene Lee and biology research assistant Alan J. Pollack to develop an implantable biofuel cell to provide usable power for the various sensors, recording devices, or electronics used to control an insect cyborg.
To convert chemical energy harvested from the insect and turn it into electricity, the team used two enzymes in series to create the anode. The first enzyme breaks down the sugar trehalose, which a cockroach constantly produces from its food, into two simpler sugars, called monosaccarides, while the second enzyme oxidizes the monosaccarides to release electrons. A current them flows as the electrons are drawn to the cathode, where oxygen from air takes up the electrons and is reduced to water.
The team inserted prototype electrodes in a blood sinus away from critical organs in the abdomen of a female cockroach. The cockroaches suffered no long-term damage, which the researchers say bodes well for long-term use.
Insects have an open circulatory system so the blood is not under much pressure. THis is unlike a vertebrate, where if you pushed a probe into a vein or worse an artery (which is very high pressure) blood does not come out at any pressure. So, basically, this is really pretty benign. In fact, it is not unusual for the insect to right itself and walk or run away afterward.
The researchers are now working to miniaturize the fuel cell so that it can be fully implanted into an insect while still allowing it to run or fly normally and examining which materials might last for a long time inside an insect. They are also working with other researchers to develop a signal transmitter that can run on little energy and also exploring how to add a lightweight rechargeable battery to the system.
After testing the system using trehalose solution, the team inserted prototype electrodes in a blood sinus away from critical organs in the abdomen of a female cockroach. The cockroaches suffered no long-term damage, which the researchers say bodes well for long-term use.
Abstract:
A biofuel cell incorporating a bienzymatic trehalase|glucose oxidase trehalose anode and a bilirubin oxidase dioxygen cathode using Os complexes grafted to a polymeric backbone as electron relays was designed and constructed. The specific power densities of the biofuel cell implanted in a female Blaberus discoidalis through incisions into its abdomen yielded maximum values of ca. 55 µW/cm2 at 0.2 V, decreasing by only ca. 5% after ca. 2.5 hours of operation.
Journal of the American Chemical Society
The New Scientist video below, from 2008, demonstrates moths and June beetles being controlled with various degrees of precision. They're not quite spies or disaster-responders yet, but with technologies such as that described in the Case Western paper, that change soon.
0 comments:
Post a Comment