Researchers at Columbia University have developed a microscopic implantable chip for physiological monitoring. It has a total volume of less than 0.1 mm3. To put that in perspective, the chip is as small as a dust mite, and can only be viewed using a microscope. The goal of this research was to create devices that can be injected using a standard hypodermic needle, and which then beam their readings wirelessly to external displays such as patient monitors and smartphones . The Columbia team used externally applied ultrasound through a conventional ultrasound imager to power and communicate with their implant. Medical implants offer huge benefits in terms of patient monitoring. Researchers are developing a host of such devices to monitor various biological parameters, from vital signs to glucose levels. However, as with other electronics, technological progress is typically coupled with miniaturization, and in the field of medical implants, smaller isn’t just sleeker, but also helps with ease of implantation and minimizing side effects. “We wanted to see how far we could push the limits on how small a functioning chip we could make,” said Ken Shepard, a researcher involved in the study, via a press release. “This is a new idea of ‘chip as system’–this is a chip that alone, with nothing else, is a complete functioning electronic system. This should be revolutionary for developing wireless, miniaturized implantable medical devices that can sense different things, be used in clinical applications, and eventually approved for human use.” The researchers report that they have created the world’s smallest single-chip system. The device uses ultrasound as a power source and to communicate with an external device. The team chose this modality as the wavelength of electromagnetic waves is too large to function with such a tiny device, whereas the wavelength for ultrasound is much smaller at a given frequency. “This is a nice example of ‘more than Moore’ technology–we introduced new materials onto standard complementary metal-oxide-semiconductor to provide new function,” said Shepard. “In this case, we added piezoelectric materials directly onto the integrated circuit to transducer acoustic energy to electrical energy.” The current iteration of the device measures body temperature, but the technology has the potential to monitor a variety of biological parameters. So far, the researchers have demonstrated that the implants can monitor body temperature in mice and hope to develop the technology to the point where it could be used in human patients. Source
