Transdermal Creatinine Sensing in Live Animals with an Integrated Electrochemical Microneedle Patch

Abstract

Abstract Over 700 million people worldwide are estimated to suffer from chronic kidney disease (CKD), and creatinine is a critical biomarker for diagnosing and managing CKD. However, conventional detection relies on invasive blood sampling and time-consuming protocols and is susceptible to interference from endogenous substances and drugs. This highlights an urgent demand for convenient, non-invasive, and accurate monitoring strategies. This study presents a wearable electrochemical microneedle (MN) patch for minimally invasive and enzyme-free creatinine detection in transdermal interstitial fluid (ISF). Solid polycarbonate MNs are coated with conductive poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate). Copper ions (Cu2+) are immobilized on the surface through immersion treatment via coordination and electrostatic interactions, and a Nafion film is finally deposited to enhance stability and anti-interference ability. Quantitative detection is based on the peak current generated from the electrochemical oxidation of in situ formed Cu0 to Cu+, which subsequently undergoes specific coordination with creatinine. The patch exhibits a linear detection range of 5.00–300 μM for creatinine with a minimum detectable concentration of 1.00 μM. Benefiting from the strong coordination effect and permselectivity of Nafion, the patch shows high stability, excellent anti-interference ability, and reliable sensing performance. Integrated with a handheld potentiostat, this compact, lightweight, and low-cost sensor achieves real-time and accurate creatinine sensing within 90 s in ISF of live rabbit models, showing great promise for long-term home-based CKD management.

The authors' abstract, as published at the source. ACS Sensors, 2026 · DOI ↗