If you have ever hovered over a piece of fish at the supermarket, wondering if it’s fresh enough for lunch (If you’re an Aussie who’s team Christmas seafood, of course, you have), you’re not alone. Freshness is one of the most significant variables in food safety, yet it’s something shoppers often rely on to gauge by a quick sniff test. Now, a team of Melbourne scientists has stepped in with a bit of breakthrough tech that could transform the way we measure it. And it’s small. Microscopically small.
Researchers at Monash University, working in collaboration with Deakin University, have unveiled the world’s first microneedle-based biosensor designed to monitor fish freshness in real time. Think of it as a tiny, high tech checker that can tell you what your nose can’t. Instead of relying on guesswork or lab heavy testing methods, this new sensor promises simple, fast and accurate readings straight from the surface of the fish.
At the heart of the innovation is something called a microneedle array. The sensor uses an electrochemical technology that reads levels of hypoxanthine, a compound that naturally rises as fish begins to spoil. Traditionally, testing hypoxanthine has involved an entire production line of steps that require grinding, filtering and centrifuging samples before they ever reach an instrument. The process is slow, expensive and firmly stuck behind laboratory doors.
This new model cuts through all of that. Instead of lengthy preparation, the microneedle array can be pressed directly onto the surface of the fish. No homogenisation. No filtration. No fancy machinery. Just a quick, direct measurement on semi-solid tissue that takes the complexity out of freshness testing. Published in ACS Sensors, the study marks the first demonstration of this technology working on fish meat in a real-world way.
Over a 48-hour monitoring period, the biosensor successfully tracked the rise of hypoxanthine as spoilage increased. In other words, it didn’t just work in theory. It worked on the meat itself, capturing changes before they were visible to the eye. According to first author and PhD candidate Masoud Khazaei, who carries out his research through the Monash Institute of Pharmaceutical Sciences and the Melbourne Centre for Nanofabrication, this is exactly where the promise lies.
“Food, especially fish meat, is extremely vulnerable to oxidation and microbiological deterioration and therefore effective analytical techniques for quality control and safety monitoring are required,” he said. He explains that by eliminating complex preparation steps, the sensor dramatically shortens the analysis period, making real-time testing a genuine possibility in the field or along the supply chain. Even more importantly, the readings closely aligned with those from a trusted commercial assay, confirming its accuracy.
Senior author Professor Nicolas Voelcker sees it as a potential turning point for the entire food sector. As a leader at MIPS, the Melbourne Centre for Nanofabrication and the Monash Department of Materials Science and Engineering, he has worked across many forms of next generation sensing technologies. He says this one shows real momentum. According to him, the sensor delivers reliable data even before spoilage becomes visible, highlighting how traditional testing can miss those crucial early changes.
It’s that early window that excites Dr Azadeh Nilghaz, a MIPS Research Fellow and project lead who also worked on the study through Deakin. She says the microneedle design offers rapid response and high sensitivity, with readings delivered in as little as 100 seconds. That makes it fit for fast paced environments where waiting for lab results simply isn’t practical.
“Freshness isn’t something we can guess, it’s something we have to measure,” she said. She explains that hypoxanthine rises well before fish looks or smells off, and catching that moment is the key to preventing spoiled food slipping through the cracks and landing on someone’s plate.
With a provisional patent already filed, the research team is now preparing to take the technology to commercialisation. If successful, we could soon see microneedle sensors becoming part of everyday food safety checks, offering a smarter, streamlined way to monitor freshness before it becomes a problem.
In a world where supply chains are stretched and food waste continues to climb, this tiny technology offers a small but significant shift. One that could make choosing the perfect piece of fish a lot less uncertain and a lot more scientific.
