Implants that change shape inside the body

Implants that change shape inside the body

An international group of researchers create devices that become flexible inside the body adapting to internal organs without losing their electronic properties

  Researchers from the universities of Texas in Dallas (United States) and Tokyo (Japan) have created electronic devices that become soft when implanted inside the body. In addition, they are able to unfold and cling to objects such as tissues, nerves or blood vessels.

These flexible transistors, biologically adaptable, could be used to help doctors learn more about what goes on inside the body. When they heat up, the devices can change shape while maintaining their electronic properties.

This research work, which appears in the scientific journal Advanced Materials is one of the first demonstrations of transistors capable of changing shape and maintain their properties after being implanted in the body, said Jonathan Reeder, graduate student in science and engineering of materials and principal author of the study.

"Scientists and doctors have been trying to introduce the electronics into the body for a while, but one of the problems was that the rigidity of the common electronics was not compatible with the biological tissue," Reeder said. "It is necessary that the device be rigid at room temperature, so that the surgeon can implant it, but soft and flexible enough to wrap three-dimensional objects and that the body behaves exactly as it would without the device. changing shape and smoothing the polymers, now we can do it. "

Polymers with memory

These shape memory polymers, developed by Dr. Walter Voit, assistant professor of mechanical engineering and materials science and co-author of the work, are the key to enabling technology.

The polymers respond to the environment of the body and become less rigid when implanted. In addition to these polymers, electronic devices are constructed with layers that include thin, flexible electronic sheets, which were first characterized in a paper published last year in Nature, and in which Reeder collaborated.

The team has manufactured the devices with an organic semiconductor, but using adapted techniques, normally applied to create this silicon electronics, which could reduce the cost of the devices.

"In the design of our device, we are getting closer to the size and rigidity of precision biological structures, but we have a long way to go to match the amazing complexity, function and organization of nature," Voit said.

These rigid devices become soft when heated. Outside the body, the device is prepared according to the position it will take inside the body. During the tests, the researchers used heat to deploy the device around a cylinder of 2.25 millimeters in diameter, and implanted the device in rats. After implantation, the device had been screwed into living tissue although it still maintained excellent electronic properties.

"Flexible electronics today is based on plastics that maintain the same shape and stiffness all the time," said Reeder. "Our research starts from a different angle and shows that we can design a device that changes shape to a more biologically compatible one."

The next step of this research will be to reduce the size of the devices so that they can wrap smaller objects, in addition to adding more sensory components to it, Reeder said.