Just as a magnetic field can make a compass needle change direction, so an electric field can pull all the little electrical charges into a different alignment, switching the charge in the opposite direction. The researchers who discovered this strange effect - Yuanming Liu and colleagues at the University of Washington, Seattle and the University of Boston - usually work on synthetic materials like these to build energy harvesting and storage devices.
But Liu knew that other unexpected electrical phenomena had been found in bone and other biological substances. And ferroelectricity was reported last year in the hard mineral coating of seashell.
Li wondered whether soft biological tissues like blood vessels might show the effect too. He and his colleagues took a thin slice of the main artery transporting blood from the heart, called the aorta, and placed it in a special microscope containing a sensitive needle tip.
The tip detected the tell-tale signal associated with ferroelectricity, and what is more, they found that they could switch this polarization with an electric field. Why on earth should any animal tissue be ferroelectric? Well, as I mentioned, the living world does make use of some unexpected material properties. Bone, for example, is piezoelectric, which as it happens is another useful kind of behaviour we rely on for everyday technologies.
It is exploited, for instance, in pressure and vibration sensors like those in your computer keyboard, because piezoelectric materials produce an electrical charge when pressure is applied to it.
It seems that bony creatures use this principle too: the electrical response to squeezing of bone helps tissues gauge the forces they experience. In seashells, meanwhile, piezoelectricity helps prevent cracks and fractures by dissipating the energy of a shock impact as electricity. The idea of transforming human body heat into electricity has been an ongoing process for scientists for years. In Sweden, for example, Stockholm Central Station uses heat exchanges to convert commuter body heat into hot water, which is then piped to an office building next door: an approach that can easily be replicated in shopping malls and supermarkets around the world.
At the University of Wisconsin, research engineers have created a shoe that utilizes reverse electrowetting to produce as much as a kilowatt of energy, just by simply taking a walk. While it is easy to capture body heat on a grand scale, such as in Sweden, there is still no easy way to harvest large amounts of waste heat on a local, wearable scale. It seems as if human batteries are a feasible goal.
It is just a matter of time and research. These proteins are called ion channels. When a cell is stimulated, it allows positive charges to enter the cell through open ion channels. The inside of the cell then becomes more positively charged, which triggers further electrical currents that can turn into electrical pulses, called action potentials.
Our bodies use certain patterns of action potentials to initiate the correct movements, thoughts and behaviors. A disruption in electrical currents can lead to illness. For example, in order for the heart to pump, cells must generate electrical currents that allow the heart muscle to contract at the right time.
Doctors can even observe these electrical pulses in the heart using a machine, called an electrocardiogram or ECG. Irregular electrical currents can prevent heart muscles from contracting correctly, leading to a heart attack. This is just one example showing the important role of electricity in health and disease. References CrashCourse. March 2,
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