By Medical Discovery News

Oct. 13, 2012

Compression of the proteins of this bacterial virus can generate small amounts of an electric current

Increasingly, the mind-blowing technology portrayed in science fiction movies comes to life in labs around the world. As engineering interfaces with the physical sciences, remarkable new advances in biomedicine happen. Two recently published studies in particular have the feel of “Star Wars.”

One involves engineering viruses to generate electricity, with the hope they’ll one day power nano-size devices implanted in the human body. These viruses, called bacteriophage, attack bacteria. Bacteriophages are simple organisms with a small number of proteins and a genome consisting of DNA or RNA, both gene-encoding molecules. The proteins coat the genome, protecting it as it enters a bacterium’s cell. It’s the unique structure of these proteins that scientists are now exploiting.

In a bacteriophage called M13, the proteins have two distinct parts. One end is positively charged and the other end of the protein, facing out, is more negatively charged. This arrangement of opposing charges at opposite ends of the same molecule can be exploited in a piezo-electric effect.

Piezo-electric means when the shape of these molecules is compressed, they generate an electric current. A mechanical button on outdoor gas grills works the same way when pressed. Researchers used the same concept to build tiny generators made out of biomolecules that could be activated by a person’s movements, such as stair climbing.

These microgenerators could potentially power implanted devices that diagnose disease or monitor therapeutic treatments. In the future, such devices might sense and report the levels of medically important compounds like glucose or neurotransmitters. A step beyond that would use microgenerators as a power source for implanted devices, such as the cochlear implant or “bionic ear” for the hearing impaired, which currently uses an external battery.

Another technology with significant implications for human health is the biological ion transistor computer chip – the first ever produced. In these biological transistors, charged molecules called ions take the place of electrons found in a traditional transistor. In essence, this means a computer chip can now network with human cells.

In recent experiments in Sweden, researchers have been using a powerful neurotransmitter called acetylcholine as the charged molecule. Acetylcholine is a muscle activator that, when released by a neuron, initiates movement. This happens when a message from the brain travels along the nerves to a muscle, like the bicep. Then a neuron transmits acetylcholine ions to nearby muscle cells, triggering the arm to move. In theory, the ion transistor could be wired and integrated into the nervous system to accomplish the same job.

In the future, this could allow fine control of muscle movement or more importantly, restore movement in people with paralysis. The experiments in Sweden have only worked with acetylcholine, but researchers believe the same technology could be used with other charged molecules. A chip could be made to balance serotonin levels, thereby acting as an antidepressant. One could even be made to monitor and boost the immune response when an invading virus or bacteria is present.

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