Scientists Develop Miniature Ultrasound Device

An original device that is tiny enough to fit into a contact lens may lead the way for a technique to conduct ultrasounds and other scientific applications. Northwestern University scientists have developed a Micro-Ring Resonator Detector, a tiny, transparent device that can benefit a range of scientific endeavors.

The device can determine the speed of the blood flow and the oxygen metabolic rate at the back of the eye, which could help doctors diagnose well-known and debilitating diseases like macular degeneration and diabetes.

Other uses may also include essential biological studies and clinical diagnosis, from nanoscopic cellular imaging to breast cancer screening. The Micro-ring builds on professor Hao F. Zhang’s work 11 years ago that combined sound and light waves to create images of biological matter.

Zhang has worked for the past three years with a research crew to form the device, which is 60 micrometers in diameter and one micron high.

“We believe that with this technology, optical ultrasound detection methods will play an increasingly important role in photoacoustic imaging for the retina and a number of biomedical applications,” Zhang said in a statement. “We needed a device that had large enough bandwidth for spatial resolution. And it needed to be optically transparent to allow light to go through freely.”

According to the study, photoacoustic imaging frequently uses piezoelectric transducers to sense laser-induced ultrasonic waves.

Still, these characteristically lack acceptable broadband sensitivity at ultrasonic frequency higher than 100 MHz, although their unwieldy size and optical methods of ultrasound detection were developed and revealed their unique applications in PA imaging. Cheng Sun, associate professor of mechanical engineering, described how the size of the device is a game changer:

“Ultrasound detection devices of that time were usually bulky, opaque and not sensitive enough,” Sun said in a statement. “And they had limited bandwidth. It could only capture part of it what was happening in the eye.”

The team plans on refining the device with support from Northwestern University, the National Institutes of Health, Argonne National Laboratory and the National Science Foundation. About twelve scientists from numerous fields have also contacted the team about adjusting it for their own work. This includes neuroscientists who have also voiced curiosity in the device as a way of studying drug protection for the cortex during different points of a stroke in a rodent brain.

“Typically, researchers use a pure piece of glass, but this allows for a lot more types of imaging,” Zhang said.

Review the study from Northwestern University.

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