The most common device that converts mechanical energy to electrical is the electrical generator – it is actually a motor run in reverse. Other ways of converting motion into electrical energy is also available, for example by using piezoelectric devices. Now, scientists have developed a new means of converting energy – using a harmless but specially engineered virus.
The device is an electrode the size of a postage stamp. The virus coating on the electrode produces enough current to drive a liquid crystal display, simply by tapping a finger on the electrode. Scientists claim they have used the piezoelectric properties of a biological material for the first time.
Electrical charge that mechanical stress can build up in solid materials is termed piezoelectricity. This principle is commonly used to harness energy from everyday events, such as walking, doors closing or opening, or even typing on a notebook. However, many of the piezoelectric material we use today are toxic.
To encourage the widespread use of safe piezoelectric materials, scientists tried using a particular virus M13 common to laboratories all over the world. M13 not only shows piezoelectric properties, it targets bacteria and is harmless to people.
The scientists wanted to confirm the piezoelectric behavior of the M13 bacteriophage. For this, they made a film from the virus and exposed it to an electric field. Inspection through a special microscope revealed moving helical proteins. These proteins coat the rods of the virus. Their movement was the final confirmation of the piezoelectric effect shown by the virus.
By genetically engineering the virus, scientists were able to boost the charges induced in the virus still further. For this, they added an extra four negatively charged amino acid residue to one end of the helical proteins of the virus. This added benefit to the use of the modified M13.
According to the scientists, the viruses self-arrange the film, enabling it to regenerate itself. The virus reproduces by infecting bacteria, generating millions of copies of its self by overnight. Scientists are of the view that such replication and self-arrangement can prove beneficial for self-assembly of Nano-technology. They boosted the charge further by stacking several virus films into layers. A stack of 20 layers provided the strongest piezoelectric effect.
The modified M13 stacks of virus made by the scientists can develop a potential difference of over 400 millivolts and capable of generating an electric current of nearly six Nano-amperes. This is enough to drive an LCD.
Imagination is the only factor limiting the applications of an M13 virus film. For instance, your laptop casing may be painted with a layer of this film. The viruses will convert any pressure from your hands into electricity and this will constantly charge the battery. In fact, when painted on the keyboard, each time you hit a key, the generated electricity will augment the battery power.
Since you can power the M13 by any kind of motion, you could conceive of powering your house by simply walking over a virus-coated floor, or power your smartphone by jiggling it in your pocket.
