Flexible electronics for implants

Microchip implants in the human body have been in the popular imagination for decades. Sci-fi authors often picture these as devices enhancing human capabilities - with the Matrix trilogy being an obvious example - whilst society seems to be slowly moving in that direction too. Electronics first appeared in our home, then in our pockets, and now major companies are starting to compete for the number one spot in the emerging market of wearable electronics.

At this pace, the next big trend could very well reside in electronic implants. In 2002 already, the United States tested a subdermal implant allowing for quick access to health-related data. But this week a team of Japanese and American scientists took this ambition a step further by creating electronic devices that become soft when implanted inside the body.

What is this softness so important? 'Scientists and physicians have been trying to put electronics in the body for a while now, but one of the problems is that the stiffness of common electronics is not compatible with biological tissue,' Jonathan Reeder, lead author of the work said in a statement. 'You need the device to be stiff at room temperature so the surgeon can implant the device, but soft and flexible enough to wrap around 3D objects so the body can behave exactly as it would without the device. By putting electronics on shape-changing and softening polymers, we can do just that.'

The device is built from so-called shape memory polymers developed by Dr. Walter Voit - an author of the paper - and thin, flexible electronic foils. Once implanted in the body, it reacts to temperature change, reshapes and grips the likes of tissues, nerves and blood vessels. When implanted in the human body, it could keep doctors informed about what is happening inside it and stimulate it for treatment.

'We used a new technique in our field to essentially laminate and cure the shape memory polymers on top of the transistors,' said Voit. 'In our device design, we are getting closer to the size and stiffness of precision biologic structures, but have a long way to go to match nature's amazing complexity, function and organization.'

During testing, researchers used heat to deploy the device around a cylinder as small as 2.25mm in diameter, and also implanted the device in rats. They observed that after implantation, the device had morphed with the living tissue while maintaining electronic properties. This had never been achieved before.

According to Reeder, the next step of the research is to shrink the devices so they can wrap around smaller objects and add more sensory components. Cordis