High-performance aptapipette sensor for ultrasensitive and specific detection of perfluorooctanoic acid in environmental water samples.

Perfluorooctanoic acid (PFOA) is a synthetic perfluorinated compound widely used in industrial and consumer products. It exhibits strong resistance to natural degradation due to its stable structure, leading to long-term environmental persistence. It poses potential carcinogenic and reproductive toxic risks, prompting global regulatory restrictions and creating an urgent need for highly sensitive detection methods. Here, we developed a PFOA detection technology based on an aptamer-functionalized nanopipette, which is referred to as an aptapipette. Glass nanopipettes were fabricated, infused with silica nanowire (SiNW) substrates via chemical etching and surface modification, then aminated and functionalized with the PFOA-specific aptamer. The detection relies on PFOA-aptamer binding-induced changes in the ion mobility of the aptapipette, with current signals acquired via linear sweep voltammetry. The aptapipette sensor shows a good linear response over 1 ng L^-1 to 10 µg L^-1 with a detection limit of 0.35 ng L^-1. The aptapipette sensor exhibits excellent specificity against perfluorinated compound analogs, ensuring minimal interference from structurally similar substances. It maintains remarkable stability over a one-week storage period, with consistent performance across repeated measurements. Validation in real environmental samples including river water, lake water and tap water yields favorable recovery rates and strong reproducibility. This technology overcomes the complexities of traditional methods such as cumbersome operations and elaborate pretreatment, offering a new strategy for monitoring environmental pollutants and holding potential in environmental toxicology and biomedical diagnostics.