Electrolytes imbalances measured in bodily fluids (blood or sweat) are useful for health assessment as well as nutrition quality control. Rapid quantification of ions such as magnesium, calcium, potassium is thus important for pathology diagnostics, and for guiding an individual’s nutrition to prevent illness. Ion-selective electrodes commonly utilized can be fragile, costly, subject to biofouling and interferences from biological samples, and require calibration and maintenance. Paper-based platforms are useful for point-of-care bioanalysis because of their simplicity, low cost, portability and disposability. We are generating micronutrients/electrolytes sensing platforms based on voltammetric solid-state ion-sensing, using potassium as our first target. Potassium levels in blood below 3 mM are indicative of abnormal heart rhythms, hypokalemia and hyperkalemia are responsible of variety of symptoms from benign to lethal.<br/>Our assay for the voltammetric quantification of potassium relies on the measurement of the shift in potential of the redox reaction of an electroactive layer, Prussian blue, as a function of the presence of the targeted potassium ion. We successfully tested solutions containing potassium ions in the health-relevant range (0-10 mM) with a reproducible trend correlating the change in redox potentials to the concentration of potassium on the paper-based devices. We also observed negligible interference from sodium, calcium and magnesium ions. Optimization of the Prussian blue deposition to improve the sensitivity of the platform and testing of human serum samples are ongoing. This paper device for detection of potassium will represent the first of a collection of solid-state electrochemical micronutrient sensors our group is developing.<br/>

Electrochemical quantification of potassium on paper-based devices

256th National Meeting (2018)

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