Aptamer lateral flow assay for the rapid detection of histamine in fish and human blood

The ingestion of histamine-rich foods or deficiencies in histamine-degrading enzymes can lead to histamine accumulation and produce intolerance, mimicking an allergic reaction with symptoms ranging from mild to even severe and potentially fatal anaphylaxis. Standard laboratory techniques like liquid chromatography are complex and lengthy, while antibody-based tests are costly and suffer from specificity issues due to the small size of the analyte. In this work, we sought to develop easy-to-use and cost-effective lateral flow assays for the rapid and accurate aptamer-based detection of histamine in fish and human whole blood. To this end, we optimised our previously selected histamine aptamer by truncation and combined it with a short partially complementary DNA probe for assay development. A microplate assay was initially designed for the detection of histamine in fish after a simple extraction procedure and the performance of the assay was comparable to standard liquid chromatographic methods. Aptamer-based lateral flow assays were then developed for the detection of histamine in fish and fingerprick blood. Canned tuna and sardines with known levels of histamine were successfully analysed, and the presence of histamine in spiked fingerprick blood samples was readily assessed by visual inspection. The limits of detection achieved were 23 nM (< 0.13 ppm) in fish and 8.4 nM (< 1 ng/mL) in blood, in combination with short duration (less than 10 minutes), in line with assay requirements for food safety control as well as rapid intervention and management of serious allergic reactions.