An international team of researchers led by the University of Glasgow have created a new type of ultra-small antenna that can wirelessly transmit data through tissue to external devices—setting the stage for tiny implantable devices capable of diagnosing, monitoring, and treating a wide range of health conditions.  

 The prototypes, dubbed µBots (pronounced ‘microbots’), are smaller, lighter, less power-hungry and produce less heat than many current implantable devices, which often rely on radio-frequency antenna to carry data, the team said.

Those devices are often difficult to use comfortably as long-term implants because they tend to be bulky and generate significant heat. This increases the risk of infection at the implant site. In contrast, the sub-millimeter-wide µBots combine acoustic and electromagnetic physics to create magnetoelectric antennas, which are smaller, cooler, and capable of carrying a more abundant stream of data across a wide bandwidth.New implantable devices may be possible with antenna breakthrough 

An international team of researchers led by the University of Glasgow have created a new type of ultra-small antenna that can wirelessly transmit data through tissue to external devices—setting the stage for tiny implantable devices capable of diagnosing, monitoring, and treating a wide range of health conditions.  

 The prototypes, dubbed µBots (pronounced ‘microbots’), are smaller, lighter, less power-hungry and produce less heat than many current implantable devices, which often rely on radio-frequency antenna to carry data, the team said.

Those devices are often difficult to use comfortably as long-term implants because they tend to be bulky and generate significant heat. This increases the risk of infection at the implant site. In contrast, the sub-millimeter-wide µBots combine acoustic and electromagnetic physics to create magnetoelectric antennas, which are smaller, cooler, and capable of carrying a more abundant stream of data across a wide bandwidth.

This is significant in that the µBots could help diagnose neurodegenerative diseases earlier, deliver drugs on demand, or even deliver neuromodulation treatments to treat conditions like epilepsy or Parkinson’s disease.

The team demonstrates how the µBots were created at the facilities of the University of Glasgow’s James Watt Nanofabrication Centre and how their performance was tested in the presence of biological tissues, further demonstrating telemetry, in a new paper published in the journal Science Advances.

The design of a part of the device that is often overlooked in piezo-antenna development is the key to the advanced performance, the team said. Rather than treating the material the device is built on as an inert base, the researchers instead harnessed the substrate to exploit its unusual acoustic resonances.

Sound waves can be bounced back and forth within the device, thanks to the property of the wafers. This generates additional frequencies called overtones that can be used for both power transfer and data transmission.

The result is an antenna with a significantly broad -10 dB bandwidth of up to 22.6 GHz, which enables it to transmit significantly more data than conventional antennas. The team successfully demonstrated this by transmitting sonogram video and audio signals wirelessly in real time between two magnetoelectric antennas–a more demanding test than binary data streams typically used to benchmark devices of this kind.

“Implantable wireless devices which can be fully enclosed inside the body instead of being tethered to external devices offer a great deal of potential for providing round-the-clock health monitoring for a wide range of conditions,” said Dr. Mahdieh Shojaei Baghini of the University of Glasgow’s James Watt School of Engineering, the paper’s first and corresponding author and the creator of these devices.

“The µBots we’re developing harness the potential of acoustic resonance to address many of the issues which have held back the technology to date,’’ she added. “We’ve shown that they are capable of transmitting a great deal of data in a way that can easily be received by existing transceiver technology.”

In partnership with colleagues in Italy, the team tested the prototypes’ performance using real biological tissues to help demonstrate their safety and functionality, a key consideration for the development of technologies designed to be implanted in bodies.

They took measurements of the antennas’ performance in rat brain tissue, human cortical brain slices, and controlled cell cultures, showing that the µBots’ performance remained reliable through each.

 “This technology could let researchers and clinicians map and modulate neural circuits with higher special selectivity while stable telemetry supports chronic electrophysiology and neuromodulation studies,” explained Dr. Adam Armada-Moreira of the University of Modena.

The team also demonstrated how performance issues can be solved using arrays of µBots when internal and external antennas fall out of angular alignment; a common challenge for implantable devices which affects their ability to communicate with each other.

The team’s tests showed that a cluster of nine of their newly-developed antennas arranged in a potential phased array can match the alignment performance of a single large RF antenna—even while staying much smaller. This makes them potentially more useful in confined spaces in the body like the brain.

The team also ran cyclic stability tests, repeatedly loading the antennas with tissue and remeasuring their properties to confirm that they remain reliable under conditions closely matching those of the real world.

In addition to researchers from the University of Glasgow and the University of Modena and Reggio Emilia, the International School of Advanced Studies, the International Iberian Nanotechnology Laboratory, the University of Rome, Harvard Medical School, and the National Interuniversity Consortium of Materials Science and Technology contributed to the research and co-authored the paper.