Biodegradable electronic devices

2 September, 2023

MBIE funds research into a new generation of Radio Frequency Identification (RFID) tags.

In 2019, the world’s mountain of electronic waste, or e-waste, reached its peak-to-date: 53.6 million metric tons, equivalent to the mass of 150 Empire State Buildings. Across the globe, researchers are developing more sustainable alternatives – materials that biodegrade, and devices that can be made, disassembled and remade, leaving behind a much smaller environmental footprint. As University of Auckland (UoA) Associate Professor Jenny Malmström explains, this is also a key motivator for one of the four core MacDiarmid Institute research strands. “The overall goal of the Reconfigurable Systems programme is to create materials that are efficient and generate zero waste. It’s also about using natural or biological materials instead of more problematic materials.” Associate Professor Malmström’s focus is on exploring the role that particular proteins could play in this effort. More specifically, she’s interested in exploring “the other things that proteins can do, beyond their obvious ‘day job’.”

For example, some species of migratory birds have proteins in their retina that are sensitive to both light and magnetic fields, making them a key navigation aid. In addition, a large number of other proteins and biological materials are piezoelectric. This means that if you stress or bend them, they can accumulate electric charge which can then be collected as a voltage. Piezoelectric materials have long been touted – and widely tested – as a means to transform mechanical motion into electricity. And Associate Professor Malmström believes that proteins with this property could be the key to making small, fully biodegradable electronic devices.

“We started with some of the fundamental science, but I wanted to push it further and see how we could make it more applied,” she says. Conversations with GNS materials scientist and MacDiarmid Institute Associate Investigator Dr Jérôme Leveneur led Associate Professor Malmström to an idea. Perhaps they could use biological materials to make RFID tags – simple, battery-free electronic circuits that can store information and be read by a radio transmitter/receiver unit. After meeting with people from different industry sectors, it became clear that there was an appetite for biodegradable ID tags. “Wildlife tracking for conservation was one key sector, as were livestock management and the food supply chain,” says Dr Leveneur. So the team decided to apply for a Smart Ideas grant from MBIE, and in October 2021 were informed that they’d been successful.

To find the right materials for the job, Associate Professor Malmström will work with her UoA colleague and fellow MacDiarmid Institute Principal Investigator Professor Jadranka Travas-Sejdic, a leading expert in degradable polymers. The team aim to integrate sensing ability in their devices. “Finding the right biological material to do that – one that is sensitive to the environment, but that stays stable over time – will be an important step.”

Incorporating piezoelectric properties into the RFID tag will lead to a battery-free device that is powered by the motion of the animal wearing it. “This tag codes information about that specific animal, and it’ll be able to transmit that as a signal over a short distance to a nearby receiver station.”