The Advantages and Challenges of Biodegradable Electronic Components

January 7, 2021 Cadence PCB Solutions

Key Takeaways

  • Soft electronic components used for medical devices reduces the need for additional surgeries.

  • Soft, transient electronic devices offer great potential for a wide range of applications in the electronics marketplace.

  • Research continues to discover new biodegradable compounds and materials for electronic devices and circuits.

During the mid-1960s, a movie called “Fantastic Voyage” captured my imagination. In the movie, saving the life of a leading scientist depended on a technology that could shrink five people and a submarine to the size of microbes. While this kind of technology does not exist yet (and probably never will), another type of amazing, worthy-of-a-science-fiction-movie technology does exist today—biodegradable electronic components. 

Biodegradable electronic components are utilized in a variety of applications, ranging from biomedical engineering to agriculture, and provide exciting new opportunities in the electronics marketplace and beyond.

biodegradable semiconductor

A biodegradable semiconductor developed by Stanford University researchers

The Advantages of Biodegradable Electronic Components

Here are some of the more advantageous properties of biodegradable electronic components:

Softness and Flexibility

Often referred to as soft electronics, biodegradable electronics can contact soft human tissue while causing little to no irritation. In addition, soft electronics have an extraordinarily high softness and flexibility that allows devices to conform to different shapes. 

Controllable Time Limits

Biodegradable electronics can have controllable time limits. Research has shown that the soft electronics used for biomedical purposes will dissolve, reabsorb, or disappear at controlled rates after the expected device lifespan. As a result, these devices become valuable as temporary medical implants that do not require additional surgeries for removal. 

Due to these unique characteristics, biodegradable electronic components are commonly used in biomedical devices.  

Biomedical Uses for Biodegradable Electronic Components 

Degrading electronic component

Stages of degradation, taken at a Stanford Research Lab.

The possibilities for biodegradable electronics that can stimulate healing and assist with regenerating tissue may usher in new medical breakthroughs. The development of micro/nanofabrication technologies has allowed researchers to create implantable devices that consist of soft polymers, biodegradable metals, thin silicon, and organic materials. 

Biosensors

Biosensors can monitor pressures, flows, strain, and chemicals within the human body and assist physicians with diagnosing physiological conditions. Along with the capability to dissolve in body fluids when no longer needed, these devices also exhibit excellent electrical characteristics. 

As an example, some types of silicone elastomers have high dielectric strength and function as dielectric layers for highly sensitive capacitive sensors used to measure pressure and oxygen levels in blood vessels. Other types have superior refractive characteristics that allow the measurement of cornea pressures.

In addition to medical applications, biodegradable electronic components have also entered the consumer electronics marketplace. 

Biodegradable Electronics in the Marketplace

The advantageous properties of biodegradable electronic components make them desirable for many electronic devices. New polyamide flexible films offer the mechanical strength, optical characteristics, and temperature resistance needed for next-generation wearable sensors— extraordinarily thin touch screens for foldable electronics. The following developments in biodegradable electronics are particularly promising:

Polyamide Films

The new wave of naturally-occurring polyamide films offers a future of thin, transparent electronic devices that biodegrade at end-of-life. For PCB design, the properties of new polyamide flexible films can eliminate the typical epoxy/acrylic adhesive layers seen with current boards and lead to very flexible, thin circuit boards.

Water-Soluble Electronic Devices

Other research has shown that water-soluble materials can work as integrated circuits and other components used for environmental sensors, medical sensors, or disposable cell phones. Called transient electronics, water-soluble electronic devices accept programming for functionality to occur for a specific time period before the device degrades into water, biofluids, or soil as waste. Thin layers of silicon used within the ICs dissolve to form environmentally-friendly silicic acid. 

Field-Effect Transistors and Ring Oscillators

In addition to working with thin silicon, research teams also developed field-effect transistors and ring oscillators from compounds consisting of silicon dioxide and tungsten. The research teams found that they could control the rate that a device would dissolve through the material thickness, ion type, ion concentration, and silicon dioxide depositing methods.

Biodegradable Silk 

One technique used to encapsulate ultrathin layers of silicon and magnesium within silk protein begins with the extraction of strong, biodegradable silk protein from silkworm cocoons. Then, the process continues by adjusting the properties of the silk protein to change the amount of degradation over time intervals. Nanomembranes consisting of magnesium interconnections, thin layers of silicon, and magnesium oxide gates work as high-quality semiconductors that can control power or sense changes of a condition within the silk protein. Because transient electronics utilize very small amounts of silicon and magnesium, the dissolution of these naturally occurring materials does not impact human health or the environment.

Optical Waveguides

Other applications for biodegradable electronic components include optical waveguides and other types of environmentally compatible photonic components. An optical waveguide allows the control and transfer of light. Silk-based polymer waveguides provide the capability to biologically modulate and sense light. 

One application for biodegradable optical electronics involves the use of edible optical sensors embedded in agricultural produce. The non-toxic optical sensors can detect harmful bacteria and then dissolve after becoming consumed with the food.

Researchers have also used spider silk to guide light through photonic devices. Continued development of the technology has shown that light flows through silk similar to how light flows through glass fibers. Given the optical characteristics of silk, research teams have integrated silk into integrated circuits and have used the silk to propagate and direct light to different sections of the circuit. Optical sensors constructed from silk can dissolve with no harm to the environment.

Challenges Facing Biodegradable Electronics 

While biodegradable medical devices offer promise, research teams continue to work to ensure that advanced polymers and biodegradable components fully dissolve and do not leave minute traces of toxic chemicals. 

Other challenges involve scaling the development of soft, transient electronic components and circuits for mass production. Those challenges dovetail with the challenge of designing circuits that deliver excellent electronic characteristics and meet design expectations before dissolving into environmentally or medically benign compounds.

The Future of Biodegradable Electronics 

Despite the challenges discussed above, the potential of biodegradable electronics seems infinite. Agricultural sensors could sensor real-time growing conditions, transmit information to farmers, and then disintegrate into the soil. Nano-sized medical devices could target individual cancer cells and reduce the need for chemotherapy. Consumer entertainment devices could dissolve at the end-of-life without contributing toxic chemicals to e-waste. Examples of defense applications include drones or robotic devices that have programmed biodegradable end-of-life routines. These are just a few examples of the ways that biodegradable electronics might change the industry—there is no denying, the future of biodegradable electronics is bright.

To keep up to date with the latest in the industry, including recent advancements regarding biodegradable electronic components, check out the PCB Design and Analysis Software page. Our Allegro PCB Editor can ensure an error-free design process for your next biodegradable electronics project.

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts

 

About the Author

Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC-2581 industry standard.

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