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.