Melbourne scientists, led by Monash University in collaboration with Deakin University, have published a study reporting the first microneedle-based biosensor for monitoring fish freshness in real time.
The electrochemical 'microneedle array' (MNA) based biosensor monitors hypoxanthine (HX) levels in fish tissue. HX levels in fish are used as an indicator of freshness, with levels rising as spoilage occurs.
Published in ACS Sensors, the teams' MNA approach is unique because, unlike traditional methods or previously developed biosensors, it does not require labor-intensive protocols including sophisticated instrumentation and extensive sample preparation such as homogenisation, filtration and centrifugation.
Instead, the MNA-based biosensor, co-designed by the Monash Institute of Pharmaceutical Sciences (MIPS), utilises a microneedle array that can be pressed on the meat surface, eliminating the need for extensive and complex sample pre-treatments and enabling direct analysis of semi-solid samples, like fish tissue.
Furthermore, the MNA-based biosensor was successfully utilised for monitoring HX levels in fish tissue samples over a 48 hour period to track concentration levels and spoilage.
Study first author and PhD candidate, Masoud Khazaei, who conducts his research through MIPS and the Melbourne Centre for Nanofabrication, said MNA-based biosensors could be ideal for low-cost, efficient and accurate in-field food testing, and/or real-time monitoring in supply chains.
"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," Mr Khazaei said.
"By eliminating the need for extensive and complex sample pre-treatments, our MNA-based biosensor was able to shorten the analysis period, therefore enhancing its suitability for real-time and on-site testing.
"Additionally, our biosensor's readings closely matched the results of the commercial Amplex™ Red Assay Kit, confirming its accuracy in detecting HX. We see real potential for MNA-based technology to reshape food quality control with its quick, accurate and cost-efficient on-site testing capabilities."
Senior author, Professor Nicolas Voelcker, who leads research programs at MIPS, Melbourne Centre for Nanofabrication and Monash University Department of Materials Science and Engineering, said "with microneedle array biosensors, we're looking at a future where food testing becomes faster, smarter and dramatically more accessible across the entire supply chain.
"Our biosensor successfully detected the progressive increase in HX concentration over time, correlating with the spoilage process and providing reliable data even before visual signs of spoilage were apparent, highlighting the biosensor's effectiveness in delivering accurate, early-stage detection that traditional methods can easily miss."
MIPS Research Fellow and project lead, Dr Azadeh Nilghaz, who partially conducted her research on this project with Deakin, said the biosensor is particularly well-suited for time-sensitive freshness assessments.
"Our biosensor has exhibited excellent analytical performance with a rapid response time of 100 seconds, making it a strong fit for time-sensitive freshness assessments," Dr Nilghaz said.
"Freshness isn't something we can guess, it's something we have to measure. Rapid, time-sensitive HX testing is essential because hypoxanthine levels rise well before fish looks or smells 'off'. That early window is our best chance to catch spoilage before it reaches consumers."
The next step for the research team will be to seek commercialisation partners in collaboration with Monash Innovation, building on the recent filing of a provisional patent for this technology.
To read the full study titled Enhancing Food Safety with Microneedle-Based Biosensors: Real-Time Monitoring of Fish Freshness click here.
DOI: 10.1021/acssensors.5c01637
