Shape-changing implantable transistors grip living tissue
A multinational group of scientists has developed implantable shape-changing transistors that can grip nerves, blood vessels and tissues. According to the researchers, these soft electronic devices can change shape within the body, while still maintaining their electronic properties, allowing them to be used in a variety of applications and treatments.
The result of a collaboration between scientists at the University of Tokyo, Japan and The University of Texas, Dallas, the soft transistors are being designed to change shape in ways that are more biologically compatible.
"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," says Jonathan Reeder, the study's lead author. "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."
To get the device to behave accordingly, the group integrated the electronics into softening and shape-changing polymer material and also added layers of flexible electronic foils. In their normal state outside the body, the transistors are rigid. Once implanted, they become soft when heated and can flex to grip living tissue.
"We used a new technique in our field to essentially laminate and cure the shape memory polymers on top of the transistors," said the team's Dr. Walter 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.”
In tests conducted in rats, the scientists heated the implanted transistors to get them to grip a cylinder 2.25 mm (0.08 in) in diameter. The device maintained its electronic properties, the researchers reported, even after it had wrapped itself around tissue.
The group's overall goal is to engineer shape changing electronic devices whose presence within the body is less intrusive as an alternative to flexible plastic-based electronic devices that continue to hold on to their shape and stiffness. Moving forward, the researchers plan to equip these soft electronics with more sensors and shrink the device's size to enable it to flex around even smaller objects.
The research is due for publication in the print version of Advanced Materialsshortly.
Check out a video of the transistor flexing around an object.
Source: UT Dallas