A paper‐based bi‐enzymatic sensor for chemiresistive glucose detection

At-home testing of glucose levels is crucial for safe monitoring of a variety of diseases, such as pancreatitis, psoriasis, cirrhosis, acute myocardial infarction, and, of course, diabetes. Current blood tests are invasive, leading to the research of alternative biofluids such as saliva, tears, and sweat. Nevertheless, such fluids are limited in quantity and contain various interfering molecules, posing stringent technological requirements. In this study, a simple paper-based glucose sensor is designed by using the conductive polymer poly(3,4-ethylene-dioxythiophene) polystyrene sulfonate (PEDOT:PSS) and a bi-enzymatic solution of horseradish peroxidase (HRP) and glucose oxidase (GOx). Unlike most electrochemical glucose sensors, this sensor employs a chemiresistive mechanism, allowing simple configurations, low costs, and easy signal measurements. The designed sensor demonstrates a working range suitable for various biofluid analyses, such as saliva, with a linear detection range of 102–104 µM while only requiring 40 µL sample volume. Detection in whole artificial saliva is carried out to demonstrate the sensors’ applicability. The limited analyte volume required, the suitable detection range, and the limit of detection achieved by this sensor make it an excellent candidate for developing a non-invasive, at-home glucose meter.