Capturing the energy produced by a beating heart, a new device can generate enough electricity to continuously power a pacemaker or heart monitor.
Since the 8th century, humans have been obsessed with idea of perpetual motion—a machine that can run forever on its own steam. True perpetual motion is impossible, but researchers are closer than ever to a battery that never dies, with a new generation of medical devices powered by piezoelectricity.
John Rogers, Ph.D., and his colleagues at the University of Illinois, Urbana-Champaign, have developed a tiny strip made of plastic and electrodes that uses the natural expansion and contraction of the heart, lungs, or diaphragm to generate up to 8 volts of electricity.
“We build plastic sheets, much like Saran Wrap, that have ultrathin ribbons of piezoelectric materials on their surfaces,” said Rogers, a professor of materials science and engineering and bioengineering. “When mounted on the surface of the heart, the beating motion induces periodic bending in the sheets. As a result of this motion, short pulses of electrical current are produced by the piezoelectric ribbons.”
The power is stored in a microchip-size battery attached to the device, and it can keep a medical implant running for (theoretically) decades. Currently, batteries to power implants like neural stimulators run out after only a few years and require surgery to replace.
“We have not seen any degradation in the properties of the devices during their use,” Rogers told Healthline. “In principle, they can last forever—or at least forever in the practical sense, compared to the lifespan of a human.”
Rogers’ team attached the piezoelectric devices to the internal organs of cow, sheep, and pigs to test how well they performed in large living mammals. They also bent and stretched the devices more than 20 million times in the laboratory.
“We have tested the devices for millions of cycles in the lab, and we now have approval for long-term survivability tests in animal models,” Rogers said. “The goal is to eliminate the need for batteries and, instead, to use natural body processes as sources of power.”
The University of Illinois researchers published the results of their experiments Monday in Proceedings of the National Academy of Sciences.
In recent years, scientists have made great strides toward growing or manufacturing human organs using stem cells.
Researchers have already successfully created simple organs like windpipes from plastic scaffolds laced with a patient’s own stem cells. The stem cells are coaxed back into infancy so they can be encouraged to grow into the right types of tissues.
And Japanese scientists have grown little liver “buds” from human cells in the lab that matured inside living mice. Implantable adult organs are still a long way off, but the groundwork is being laid as we speak.
Does this mean that devices to aid ailing organs—and the batteries that power them—will become obsolete?
“Perhaps, but we see a future of ‘electroceuticals’ in which the type and number of electronic devices inside the body is increasing, not decreasing,” Rogers said. “The power of electronics can, in conjunction with traditional pharmaceuticals, yield important improvements in human health and lifespan.”