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Biodegradable Power Generators Could Power Medical Implants

Whole medical implants could dissolve in the body

2 min read
Biodegradable Power Generators Could Power Medical Implants
Photo: Beijing Institute of Nanoenergy and Nanosystems/Chinese Academy of Sciences

Biodegradable devices that generate energy from the same effect behind most static electricity could help power transient electronic implants that dissolve in the body, researchers say.

Implantable electronic devices now help treat everything from damaged hearts to traumatic brain injuries. For example, pacemakers can help keep hearts beating properly, while brain sensors can monitor patients for potentially dangerous swelling in the brain.

However, when standard electronic implants run out of power, they need to be removed lest they eventually become sites of infection. But their surgical removal can result in potentially dangerous complications. Scientists are developing transient implantable electronics that dissolve once they are no longer needed, but these mostly rely on external sources of power, limiting their applications.

Now researchers have developed a biodegradable power source that harnesses the phenomenon known triboelectricity, the most common cause of static electricity. When two different materials repeatedly touch and then separate, the surface of one material can steal electrons from the surface of the other. This is why rubbing feet on a carpet or a running a comb through hair can build up electric charge. The scientists detailed their findings online in the 4 March edition of the journal Science Advances.

At the heart of the new device are two layers of commercially available, inexpensive, biodegradable polymers, such as PLGA and PCL, which are used in medical sutures. One layer is a thin flat film, while the other layer is a sheet coated with rods up to 300 nanometers high. The layers are separated from one another by blocks of biodegradable polymer; they generate electricity when they are pushed together and pulled apart.

In the lab, the researchers found that their biodegradable nanogenerator could achieve a power density of 32.6 milliwatts per square meter. They discovered that it could successfully power a neuron-stimulation device that helps control neuron growth. “Our results open the gate to fully degradable electronic devices,” says study co-author Zhong Lin Wang, a materials scientist at the Beijing Institute of Nanoenergy and Nanosystems. “A whole device can be absorbed in body and would not need to be removed through additional surgery.”

The researchers note that they can tune the lifetime of their nanogenerator from hours to years, depending on the needs of the implantable electronics it is designed to power. They suggest that future devices could be powered by the mechanical energy from heartbeats or respiration.

“We provide a potential power source by reclaiming biomechanical energy from the human body,” Wang says.

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A photo showing machinery in a lab

Foundries such as the Edinburgh Genome Foundry assemble fragments of synthetic DNA and send them to labs for testing in cells.

Edinburgh Genome Foundry, University of Edinburgh

In the next decade, medical science may finally advance cures for some of the most complex diseases that plague humanity. Many diseases are caused by mutations in the human genome, which can either be inherited from our parents (such as in cystic fibrosis), or acquired during life, such as most types of cancer. For some of these conditions, medical researchers have identified the exact mutations that lead to disease; but in many more, they're still seeking answers. And without understanding the cause of a problem, it's pretty tough to find a cure.

We believe that a key enabling technology in this quest is a computer-aided design (CAD) program for genome editing, which our organization is launching this week at the Genome Project-write (GP-write) conference.

With this CAD program, medical researchers will be able to quickly design hundreds of different genomes with any combination of mutations and send the genetic code to a company that manufactures strings of DNA. Those fragments of synthesized DNA can then be sent to a foundry for assembly, and finally to a lab where the designed genomes can be tested in cells. Based on how the cells grow, researchers can use the CAD program to iterate with a new batch of redesigned genomes, sharing data for collaborative efforts. Enabling fast redesign of thousands of variants can only be achieved through automation; at that scale, researchers just might identify the combinations of mutations that are causing genetic diseases. This is the first critical R&D step toward finding cures.

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