High accuracy determination of multi metabolite by an origami-based coulometric electrochemical biosensor

Abstract In this work, we present an origami-based coulometric electrochemical biosensor for high-accuracy determination of multi metabolite on one single electrode with only 0.5 μL samples. The proposed biosensor was fabricated with a screen-printed electrode and an origami device that was equipped with three foldable tabs preloaded with diverse oxidases. The origami device with a hole in its center was pasted onto the screen-printed electrode to form a reaction cell for electrochemically electrolyzing the target analytes with the corresponding oxidases. As a demonstration, L-lactate, cholesterol, and glucose as the target analytes were successfully detected with this biosensor. The values of electric charge for the L-lactate, cholesterol, glucose oxidation by integrating the Faradaic current vs. time were in good agreement with the theoretical values. The linear ranges of detection were respectively 0–10 mM (L-lactate), 0–5 mM (cholesterol), 0–24 mM (glucose) with efficiency electrolysis 99% ± 3%, 99% ± 1%, 100% ± 2% (n = 3, n: number of repetition). And the limit of detection of L-lactate, cholesterol, glucose was 0.25 mM, 0.23 mM, 0.03 mM respectively. The applicability of the device in POCT was performed in serum. And the above 95% recovery rate indicated it was suitable for the clinical application. Additionally, the proposed biosensor could be a candidate for more other metabolites detection, such as fructose, glutamate, bilirubin, and galactose. The origami paper-based electrochemical biosensor provided a facile and controllable device to perform the coulometry in the determination of multi metabolite.