Transient Electronic Components Can Degrade in Days

A new semiconducting polymer degrades away in a weak acid, opening up the potential for electronic devices that do not leave behind toxic waste when they pass their prime.

Researchers at Stanford Univ. created a conjugated polymer made from diketopyrrolopyrrole (DPP) with imine linkages as the basis for their new system, which they call a transient electronic device. They also invented a new form of cellulose substrate. The ultimate goal is to make sensors and monitoring devices that can work in and on the human body and degrade into nontoxic components once their work is done, says Zhenan Bao, a professor of chemical engineering and materials science at Stanford Univ.

Bao and her lab have long been interested in using human skin, which is stretchable, self-healing, and biodegradable, as the inspiration for designing electronic components. The team has managed to create both stretchable and self-healing semiconductors and conductors and is now tackling biodegradability. The challenge, Bao says, is that most biodegradable polymers rely on ester bonds, which can be hydrolyzed under the conditions found in the body. Bioimplants need to be stable until they are triggered to decay.

▲Engineers at Stanford Univ. have developed a flexible, biodegradable semiconductor, shown here draped over a human hair, that could be the basis for implants that dissolve after they have served their purpose. Image courtesy of Zhenan Bao’s Lab...