NiHCF@PDAP-Enhanced Wearable Microneedle Biosensor for Continuous and Lifetime-Prolonged Monitoring of Uric Acid in Interstitial Fluid

Personalized healthcare requires convenient and high-fidelity approaches to monitoring metabolic biomarkers, for example, uric acid (UA), toward next-generation disease management. Although wearable microneedle-based devices stand out with miniaturized needle-like sensors capable of transdermal monitoring of UA in interstitial fluid (ISF) in an imperceptible manner, their rigid nature and limited lifespan pose considerable challenge to the practicability as continuous biosensors in real-world application. Here, we present a wearable microneedle-based biosensor that integrates the strength of microneedle with a Prussian Blue analog, that is, nickel hexacyanoferrate, enhanced sensing interface to minimally invasive access UA in ISF and enable highly blood-correlated, continuous, and long-term monitoring. By incorporating conductive poly(2,6-diaminopyridine), the as-proposed microneedle biosensor renders highly sensitive monitoring of UA with a detection limit of 1.78 μM. In addition, the fully integrated device features prominent mechanical resilience and flexibility against undesirable physical deformations, ensuring reliable sensing performance of UA in daily activities. In animal models, the resulting biosensors achieved dynamic UA tracking with excellent stability and captured prolonged amperometric information interpreting the metabolic changes of UA levels during a seven-week in vivo experiment. The strong correlation between the obtained ISF and blood UA levels demonstrated the high analytical accuracy of the biosensor, which, thus, provided a powerful approach to fulfill personalized UA management in the future.