Whole Blood Theophylline Measurements Using an Electrochemical DNA Aptamer-based Biosensor

Theophylline, a bronchodilator used in the treatment of respiratory diseases, displays a narrow therapeutic range requiring therapeutic drug monitoring to maximize its effectiveness and safety. Current measurements of theophylline concentrations are, however, achieved using chromatography or immunoassays, which, in spite of their high accuracy and sensitivity, rely on expensive laboratory-based instruments operated by trained personnel or provide only semi-quantitative results, respectively. In response, we developed an electrochemical DNA aptamer-based (E-AB) sensor for theophylline on screen-printed electrodes. Our sensors enable rapid (<30 s) and selective measurements against theophylline structural analogs in clinically relevant range (55–110 μM) in finger-pricked-sized volumes of undiluted blood samples (<100 μL). Given these attributes, we envision that our results contribute to the development of a low-cost and convenient sensing device for molecular monitoring at the point-of-care.