Transient Electronics Simply Dissolve After Use
April 8, 2013

Dissolvable Electronics May Be The Wave Of The Future

Enid Burns for — Your Universe Online

Imagine a world where an electronic device disappears after it's no longer needed. That world may be closer than you think. New "transient electronics" are in experimental stages, and were presented at the 245th National Meeting & Exposition of the American Chemical Society (ACS) annual meeting in New Orleans. The new transient electronics were shown among 12,000 reports on new scientific advances and other presentations.

Transient electronics have a number of uses, including medical devices injected to relieve pain, or fight an infection; or producing products with a pre-engineered service life. After use, these small chips simply disintegrate. In the case of a medical use, it might dissolve harmlessly in the bloodstream or tissue to be processed out by the body.

The new approach, dissolving electronics, is counter to the current design structure of electronic chips, which is to produce electronics that last — sometimes beyond their actual functional life. The current practice began 50 years ago, researchers say.

"The goal of the electronics industry has always been to build durable devices that last forever with stable performance," said John Rogers, PhD from the University of Illinois at Urbana-Champaign, who led the research. "But many new opportunities open up once you start thinking about electronics that could disappear in a controlled and programmable way."

The new electronics could be used for a range of devices. Applications include use in cell phones and other mobile devices that stop working on a timetable corresponding to the time for upgrading to a new model. The new type of chips could reduce e-waste, a problem that amounts to roughly $50 million per year in discarded electronics.

The field of medicine stands to benefit from transient electronics as well. Implants can serve a specific and time-limited purpose — pain relief, fighting infection, diagnosis or to stimulate healing after surgery. After the electronic component fulfills its task, it could disappear without the need for an additional extraction surgery.

Transient electronics could also be used for environmental monitors. In a report on the technology, researchers say that transient electronics could be used to produce water-quality sensors to monitor the water quality of rivers and other water sources. Normally, such devices have to be retrieved after the study. After reporting its results, a monitor could simply dissolve into the river.

The report did not offer specifics as to how these electronics dissolve or what chemicals or other materials they might leave behind.

The transient electronics developed by Rogers´ team are not the first bioresorbable medical devices that can disappear in a body over time. However, they say that they are the first to produce such a broadly applicable technology.

The transient electronics can be built with temperature sensors, solar cells and miniature digital cameras, among other features. The team says that previous bioresorbable devices were made of different materials that only partially dissolved and thus left behind residues.

The Urbana-Champaign team says: "The electronics are enclosed in material that dissolves completely after a certain period of time when exposed to water or body fluids, somewhat like dissolvable sutures. By altering the number of layers of the wrapping, scientists can define everything about how the device will dissolve in a body or in the environment, including its overall lifetime," Rogers said in the report.

Devices are expected to perform as they do in conventional electronics and function normally until the encapsulating layer disappears. "Once that happens, it takes about 30 minutes for the electronic connections to dissolve away, and the device stops working," the report says.

In some applications, transient electronics will be able to operate without an external electricity source. "For instance,” Rogers explained, “the latest transient electronic devices incorporate zinc oxide, which is 'piezoelectric.' It means that thin, flexible devices made with zinc oxide could produce electricity when bent or twisted — perhaps by movement of muscles in the body, pulsation of blood vessels, or beating of the heart."

The group at the University of Illinois at Urbana-Champaign has received research funding from the Defense Advanced Research Products Agency, the National Science Foundation, the Air Force office of Scientific Research Multi University Research Initiative program, the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award EB002520 and the U.S. Department of Energy.