Accurately detecting peanut allergens in processed foods is challenged by manufacturing processes that can alter protein structure and reduce the reliability of conventional protein-based methods such as immunoassays. A novel DNA-based approach has been proposed using an electrochemical biosensor designed to detect the gene for Ara h2, one of the most clinically important peanut allergens.
Researchers developed a label-free assay built around magnetic beads coated with DNA probes that selectively capture Ara h2 DNA sequences. Rather than relying on enzymes or fluorescent labels, the system measures changes in electrical impedance when the target DNA is present. This simplifies the analytical workflow while maintaining high sensitivity. The magnetic beads separate and concentrate target DNA before measurement, thereby reducing interference from complex food matrices and improving reproducibility.
The biosensor detected Ara h2 DNA across a wide concentration range and was able to distinguish the target sequence from closely related non-target DNA. Importantly, it performed well in soy beverages, rice beverages and cow’s milk, achieving recoveries close to 100 per cent and showing minimal matrix interference. The capture probe-coated magnetic beads also remained stable for at least 20 days, an improvement over some previously reported Ara h2 DNA sensors.
While further work is needed to validate the approach, the study demonstrates how DNA-based biosensing could complement existing allergen detection methods, particularly for highly processed products where protein integrity may be compromised.
Reference: Hervás-Pérez, et al. (2026) ‘Magnetic Beads-Based Electrochemical Label-Free DNA-Bioassay for the Detection of Peanut Allergen Ara h2 in Food Matrices’, Biosensors, 16(7), 387. Available with Open Access at: https://doi.org/10.3390/bios16070387.
