Transient electronics, also known as biodegradable electronics, is an emerging technology being explored across many fields and for various applications. When used in healthcare, biodegradable materials incorporated into medical devices could be valuable for diagnostic and therapeutic purposes. Some of the potential operations include monitoring intracranial pressure, assisting wound healing processes, identifying neural networks, and more.

Benefits of Transient Electronics

While generally most electronics are manufactured for longevity and stability, attention is now turning to the development of devices which possess a transient, or temporary, function. These devices are made of biodegradable materials that can partially or completely dissolve, resorb, or physically disappear after completing their assigned task.

When used as a temporary implant, the unit is designed to be safely absorbed by the patient's body -- very similar to resorbable sutures or cardiovascular stents. This means that a second surgery or invasive procedure is no longer needed for device retrieval, thereby decreasing the risk of infection or other complications.

They are also being referred to as "green electronics." By introducing biodegradability to consumer electronics and monitors, proponents predict less electronic waste ending up in landfills and lower associated risks and costs resulting from recycling operations. Another inherent benefit is that transient electronic devices can be used as data-secure hardware. Since they will self-destruct by design, the information contained within them is protected from unauthorized access after completing their function.

Biodegradable Electronic Materials

The science of building transient electronics relies in part on the extensive study of existing biodegradable organic materials already being used as implants, including sutures, stents, scaffolds for regenerative medicine, etc. The function of these units is defined by their structure and mechanics and they often serve as passive components within the devices.

Inorganic elements such as semiconductors, dielectrics, and metals have both superior electronic properties and excellent degradation behavior. When combined, the organic and inorganic categories of materials make possible the creation of high-performance sensors and active devices that will expand the applications of transient electronics.

While the degradation of inorganic materials has been studied for many years, it is in the context of corrosion science with most studies focus on materials in bulk and extreme environments (strong acid or base solutions). New studies will investigate degradation in biological solutions of materials in the thin film format relevant to electronic standards. 

Laboratory testing has established degradation rates of dissolvable thin film electronic materials mostly in deionized (DI) water and simulated biofluids (phosphate buffered saline and solutions). Scientists note that laboratory results may differ from in vivo degradation due to the presence of cells and proteins. In fact, recent studies show that proteins can possibly slow dissolution rates of silicon.

Biodegradable Devices in Use Today

Completely dissolvable devices include:

• thermal therapy systems to prevent post-surgery infection
• dissolvable stretchable electrophysiological and pH sensors
• temperature sensor
• implantable drug delivery systems with a programmable release
• bioresorbable electronic stent
• degradable power devices (radio frequency electronics)
• bioresorbable intracranial pressure sensor
• supercapacitor and battery
• bioresorbable neural recording system

Partially biodegradable devices include:

• organic thin film transistor on PLGA substrates
• high-performance green electronics on biodegradable cellulose nanofibril paper
• eco-friendly transistors based on totally disintegrable and biocompatible semiconducting polymers on a cellulose substrate
• edible electronics (circuits, supercapacitor, and battery)

Although many challenges remain for the researchers and developers of viable and clinically effective transient medical electronics, the future is bright for this emerging technology. The potential and promise for these applications are driving materials strategies, manufacturing schemes, and device layouts for biodegradable electronics.

Some suggested areas to focus on include expanding the biodegradable materials database to study materials chemistry, materials-biology interface, and associated biocompatibility. Device architecture and design using transient materials need improvement to effectively combine electrical performance that meets practical clinical standards with the desired level of biodegradation.

Conclusion

Transient electronics have the potential to improve medical outcomes, benefit the environment, and ensure data security. Valid reasons, indeed, for continued investigation.