| Abstract |
Agriculture is vital to Thailand’s economy. However, the use of herbicides such as atrazine pose a significant risk to human health, animals and the environment. These chemicals are designed to persist in soil and on plants for weeks in order to stop weed growth, but as a result they can accumulate in plants and water that human consume which in turn exposes us to unsafe levels of these chemicals (0.003 mg/L in water; US Environmental Protection Agency). As a result, there is a need for accurate and sensitive detection of atrazine. Current methods rely heavily on laboratory-based techniques, which are timeconsuming, costly, and require trained operators to operate specialised equipment. Field-based methods exist, but they are either non-specific (acetylcholinesterase) or have higher production costs and lower component stability (antibodies). DNA aptamers are an interesting alternative as they are cheap to produce and normally easy to convert into a field-testable format. However, the most sensitive existing atrazine aptamer can only be used with laboratory-based isothermal titration calorimetry at present. In this work, a strand displacement aptamer system is explored to overcome this limitation. A range of oligonucleotides complementary of the aptamer are designed and the ability of atrazine to bind to the aptamer and displace these complementary oligonucleotides is evaluated. Ultimately the goal is to modify the atrazine-specific aptamer with a fluorescent dye at the 5' end. In the absence of atrazine, the aptamer hybridises with a complementary DNA strand containing a quencher at the 3' end, resulting in fluorescence quenching. In the presence of atrazine, the aptamer preferentially binds to the target molecule displacing the quencher strand and leading to fluorescence emission. This strand displacement mechanism potentially enables the direct and real-time detection of atrazine residues with high sensitivity and selectivity. |
Publication
Journal Publication
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