Multifunctional Dopamine-Based Hydrogel Microneedle Electrode for Continuous Ketone Sensing.

Diabetic ketoacidosis (DKA), a severe complication of type 1 diabetes (T1D) is triggered by production of large quantities of ketone bodies, requiring patients with T1D to constantly monitor their ketone levels. Here, we report a skin compatible hydrogel microneedle (HMN)-continuous ketone monitoring (HMN-CKM) device. The sensing mechanism relies on the catechol-quinone chemistry inherent to the dopamine (DA) molecules that are covalently linked to the polymer structure of the HMN patch. The DA serves the dual-purpose of acting as a redox mediator for measuring the byproduct of oxidation of 3-beta-hydroxybutyrate (β-HB), the primary ketone bodies, while also facilitating the formation of a crosslinked HMN patch. A universal approach involving pre-oxidation and detection of the generated catechol compounds was introduced to correlate the sensor response to the β-HB concentrations. We further showed that real-time tracking of a decrease in ketone levels of T1D rat model is possible using the HMN-CKM device in conjunction with a data-driven machine learning model that considers potential time delays. This article is protected by copyright. All rights reserved.