A User-Centered Approach in the Development of a Label-Free Impedimetric Chemiresistor for H₂O₂

A strong focus on laboratory optimization in new sensing technology often delays and sometimes prevents successful real-world implementation. Accordingly, we present a proof-of-concept impedimetric chemiresistor (ICR) for a noninvasive, point-of-care device that combines the development of a novel electrochemical sensing modality with a user-centered approach. The ICR features a two-electrode design fabricated by using a low-cost, scalable roll-to-roll (R2R) flexographic printing technique and a zeolitic imidazolate framework-8 (ZIF-8) chemiresistive channel. Here, we demonstrated the ICR's response to hydrogen peroxide (H₂O₂) as an initial step toward a noninvasive hypoglycemia diagnostic tool. The ICR exhibits a linear impedance response to H₂O₂, with a limit-of-detection of 3.7 mM, a dynamic range of 4-60 mM, and preliminary validation in human saliva. Early user feedback guided device design and highlighted how incorporating usability throughout development supports the successful transition from a lab prototype to a real-world healthcare technology.