Portable and sensitive detection of peanut allergen Ara h 1 via a CRISPR/Cas12a-integrated personal glucose meter using polydopamine-functionalized pipette tips.

A portable biosensor for the peanut allergen Ara h 1 was developed by integrating a polydopamine-functionalized pipette tip, CRISPR/Cas12a signal amplification, and a personal glucose meter. Ara h 1 binding induced partial displacement of a cDNA activator, which activated Cas12a trans-cleavage and released glucose oxidase from GOx-DNA conjugates. The released enzyme catalyzed glucose oxidation, producing a quantitative decrease in glucose concentration. Under optimized conditions, the assay showed a linear range of 50-1000 ng/mL and a solution-based limit of detection of 22.19 ng/mL. Post-extraction matrix-spike tests in commercial peanut-biscuit and peanut-beverage extracts yielded recoveries of 101.58-104.68% with relative standard deviations below 3.44%. These results demonstrate the analytical feasibility and preliminary matrix compatibility of the platform, although validation using pre-extraction fortified, incurred, and naturally contaminated foods is still required.