Research integrates CMOS into flexible substrates for medical implants

A new technology has been developed that allows low power CMOS devices to be easily integrated into flexible substrates for medical implants. The researcher, Yong Xu, associate professor of electrical and computer engineering in the College of Engineering at Wayne State University in Detroit, said the technology uses SOI CMOS devices and two layers of a polymer called Parylene C, one of which is perforated, to bond them to flexible substrates.

Xu's technology has an advantage over existing methods, such as direct fabrication on flexible substrate and transfer printing, in that it is SOI-CMOS compatible. "The ultimate goal is to develop flexible and stretchable systems integrated with electronics, sensors, microfluidics and power sources, which will have a profound impact on personalized medicine, telemedicine and health care delivery."

The lamination of the electronics between those parylene layers offers the additional benefit of protection from environmental moisture. Xu said Parylene C, which creates a flexible skin, already has been used in other medical applications and is well tolerated by human tissue.

His process allows more high-performance electronic devices to be attached to the flexible surface by eliminating the transfer printing step, in which electronics are removed from a harder surface and integrated into a softer one. Additionally, the process allows various sensors and microfluidic devices to be integrated into the flexible substrate.

Xu said his technology could result in retinal prostheses that cause less tissue irritation and therefore work better and longer, as well as more comfortable wearable health monitoring devices. Other possible applications include balloon catheters and stents.

- Nick Flaherty
??EE Times