Widely used to monitor and map biological signals, to support and improve physiological functions, and to treat disease, implantable medical devices are transforming healthcare and improving the quality of life for millions of people. Researchers are increasingly interested in the design of wireless miniaturized implantable medical devices for physiological monitoring in vivo and in situ. These devices could be used to monitor physiological conditions, such as temperature, blood pressure, glucose, and respiration for diagnostic and therapeutic procedures.
To date, conventional implanted electronics have been very inefficient in terms of volume – they typically require multiple external chips, packages, wires, and transducers, and batteries are often required for energy storage. A constant trend in electronics has been a closer integration of electronic components, often moving more and more functions onto the integrated circuit itself.
Columbia Engineering researchers report that they have built what they say is the world’s smallest single-chip system, consuming a total volume of less than 0.1mm3. The system is as small as a mite and visible only under a microscope. To do this, the team used ultrasound to power and communicate with the wireless device. The study was published online May 7 in Scientific progress.
“We wanted to see how far we could push the boundaries of the small size of a functional chip that we could make,” said study leader Ken Shepard, professor of electrical engineering at Lau Family and professor of biomedical engineering. . “It’s a new idea of ’chip as a system’ – it’s a chip that alone, with nothing else, is a fully functional electronic system. This should be revolutionary for the development of miniaturized wireless implantable medical devices capable of sensing different things, to be used in clinical applications and eventually approved for human use. “
The team also included Elisa Konofagou, Robert and Margaret Hariri Professor of Biomedical Engineering and Professor of Radiology, as well as Stephen A. Lee, PhD student at Konofagou Laboratory who participated in animal studies.
The design was carried out by doctoral student Chen Shi, who is the study’s first author. Shi’s design is unique in its volumetric efficiency, the amount of function contained in a given amount of volume. Traditional RF communication links are not possible for such a small device because the wavelength of the electromagnetic wave is too large for the size of the device. Since ultrasound wavelengths are much smaller at a given frequency, because the speed of sound is much lower than the speed of light, the team used ultrasound to power and communicate with the device without thread. They fabricated the “antenna” to communicate and feed with ultrasound directly on top of the chip.
The chip, which is the implantable / injectable assembly without additional packaging, was manufactured by the Taiwan Semiconductor Manufacturing Company with additional process modifications performed in the Columbia Nano Initiative cleanroom and the City University of New York Advanced nanofabrication. Science Research Center (ASRC) Establishment.
Shepard commented, “This is a great example of ‘more than Moore’ technology – we introduced new materials over a standard complementary oxide-metal-semiconductor to provide a new function. In this case, we added additional features. piezoelectric materials directly on the integrated circuit of the transducer. acoustic energy into electrical energy. “
Konofagou added, “Ultrasound continues to gain clinical importance as new tools and techniques become available. This work continues this trend.”
The team’s goal is to develop microchips that can be injected into the body with a hypodermic needle and then communicate outside the body using ultrasound, providing information about something they are measuring locally. Current devices measure body temperature, but the team is working on many more possibilities.
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Material provided by Columbia University School of Engineering and Applied Sciences. Original written by Holly Evarts. Note: Content can be changed for style and length.