Development of an aptamer-based lateral flow test for the quantitative detection of mycotoxins

• Applicant: Dr. Monika Conrad
• Subject Area: Analytical Chemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543397457

Mycotoxins are organic molecules that can cause serious diseases in the body even in low concentrations. They are naturally occurring low-molecular metabolites of various species of moulds, although their exact function has not yet been elucidated. Since these mould species also occur on and in foodstuffs, their frequent occurrence is of extraordinary relevance, especially for humans, because of their toxicity. In particular, the conditions of cultivation and storage can lead to a local proliferation of these moulds in food processing plants, which is difficult to predict. A test directly at the point of need is required to quickly identify such mycotoxin contaminated food and to minimise the health risk and financial consequences,.Such a test helps to ensure that countermeasures can be taken directly, protecting consumers, and avoiding costly recalls. The lateral flow assays (LFAs) presented in this application feature low manufacturing costs, ease of use, on-site application, and rapid results. These properties make them the ideal technology for mycotoxin testing, particularly regarding use by personnel with little training. Commercially available LFAs usually test for only one analyte and provide a purely qualitative result, but this is not sufficient for the described application. The aim of this research proposal is therefore to develop an assay for the parallel, quantitative determination of multiple mycotoxins. Aptamers will be utilised as the recognition element in the LFA instead of the commonly used antibodies, as they have several advantages such as higher stability, higher reproducibility and lower costs compared to antibodies. For LFA development, aptamers are labelled with gold nanoparticles, which are commonly employed in LFAs due to their stability and intense colour. The colour intensity on the test strips is evaluated, for which the signal is captured by a camera and the concentration of the analyte (the mycotoxin) can be inferred using the standard addition method. The standard addition method allows an internal calibration independent of matrix effects and can compensate for inter-batch variations for a reliable, robust, and quantitative interpretation of the results. Three new design options for realising the standard addition method on the LFA will be tested. The first design option uses laser-structured test strips that clearly separate the standard additions. The second design option exploits the effect of laminar flow and examines whether hydrophobic barriers are necessary. The addition of standards is achieved by spotting an array of test line reagents and analyte solution. The third design option investigates whether reducing the test line reagent can also produce the effect of a standard addition. The aim of this application is to develop an LFA that allows both the parallel detection of different mycotoxins by multiple test lines and their quantification via the standard addition method on structured LFAs.

• DFG Programme: WBP Fellowship
• International Connection: Canada
• Host: Professorin Maria C. DeRosa