This study identifies an aptamer that selectively binds to perfluorooctanoic acid (PFOA). Upon binding, the aptamer produces fluorescence, which can be used to detect and provide semi-quantitative measurements of PFOA in water matrices.
Perfluorooctanoic acid (PFOA) is a toxic, bioaccumulative chemical that is present globally in water. Its level in water is regulated in most countries but would require access to analytical instruments for routine measurements to enforce against regulations. Here, we develop aptamers as a detection mechanism for PFOA. In this study, we selected 16 candidates for PFOA aptamers in order to find a selective and sensitive aptamer. After 30 rounds of selection, one candidate, Candidate 9, showed a measurable binding affinity with a kd of 2 µM and demonstrated no binding to other chemicals that are similar in terms of structure to PFOA. 2D structure analysis demonstrated an enrichment of hairpin structure, especially after the addition of counter-selection. The selected aptamer showed 2.8 times the signal when incubated with PFOA and did not produce signal with other PFAS or chemicals used in counter-selection. When applied to real water samples, the aptamer's detection mechanism was changed but retained its ability to detect PFOA in drinking water. This study paved the way to developing an aptamer-based system that can detect PFOA without the need to access lab-based analytical instruments.
Perfluorooctanoic acid (PFOA) is a toxic, bioaccumulative chemical that is present globally in water. Its level in water is regulated in most countries but would require access to analytical instruments for routine measurements to enforce against regulations. Here, we develop aptamers as a detection mechanism for PFOA. In this study, we selected 16 candidates for PFOA aptamers in order to find a selective and sensitive aptamer. After 30 rounds of selection, one candidate, Candidate 9, showed a measurable binding affinity with a kd of 2 µM and demonstrated no binding to other chemicals that are similar in terms of structure to PFOA. 2D structure analysis demonstrated an enrichment of hairpin structure, especially after the addition of counter-selection. The selected aptamer showed 2.8 times the signal when incubated with PFOA and did not produce signal with other PFAS or chemicals used in counter-selection. When applied to real water samples, the aptamer's detection mechanism was changed but retained its ability to detect PFOA in drinking water. This study paved the way to developing an aptamer-based system that can detect PFOA without the need to access lab-based analytical instruments.
WDRC KAUST