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Aptamer-based lactate sensor can monitor metabolism

Fluorescent readout triggered when DNA aptamer binds the small metabolite

by Laurel Oldach
January 27, 2023


A reaction scheme shows a fluorescently tagged linear DNA molecule dissociating from a quencher and adopting a stem-and-loop structure when lactate is added.
Credit: Huang & Liu/Angew. Chem. Intl. Ed.
When a fluorescence-tagged DNA aptamer (green and yellow) binds to lactate, it separates from a complementary DNA strand tagged with a quencher (orange). The separation removes the quenching, allowing a fluorescent readout of lactate level.

When organisms break down glucose in low-oxygen environments, the end product is lactate. Most ways to measure this metabolite—to monitor athletic performance or diagnose diseases, for example—depend on enzymes. Now, researchers report a DNA aptamer that can bind L-lactate at physiological levels (Angew. Chem., Intl. Ed. 2023, DOI: 10.1002/anie.202212879).

Detection based on DNA aptamers, short sequences with a stem-loop structure that can bind other molecules, tends to be more temperature stable and reversible than enzymatic methods. A team led by Juewen Liu of the University of Waterloo developed an aptamer that binds to L-lactate when magnesium is present. According to Liu, the Mg2+ ions may form a bridge between the negatively charged DNA and the small, negatively charged lactate molecule. The researchers then turned the aptamer into a fluorescent sensor whose ability to detect a large range of lactate levels compares well with commercially available assays. The sensor works on blood serum and can be combined with a previously published glucose aptamer to track metabolic activity.


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