One-Step Electrochemical Modification of PEDOT:PSS/PBNPs Hybrid Hydrogel on the Screen-Printed Electrode Surface for Highly Sensitive Detection of Creatinine

Creatinine (CRE) is frequently measured in clinical practice due to its recognized significance as a pivotal biomarker across a spectrum of renal and cardiovascular disorders. However, the rapid and accurate detection of CRE for assessing kidney and muscle functions remains challenging. Here, we prepared the poly(3,4ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hydrogel uniformly loaded with Prussian blue nanoparticles (PBNPs) via a one-step metal-assisted electrochemical modification method on the screen-printed electrode for ultrasensitive CRE detection. The conductive, porous PEDOT:PSS/PBNPs hydrogel provided a confined space that facilitated highly efficient biocatalytic cascade reactions of creatinine amidohydrolase, creatine amidinohydrolase (Cl), and sarcosine oxidase, enabling the CRE detection with a high sensitivity (40.2 μA mM^–1 cm^–2), a wide linear detection range (20–600 μM), and a low detection limit (8.3 μM). What is more, we developed an integrated platform utilizing a differential strategy to eliminate the interference from endogenous creatine (CR), employing a dual-channel working electrode for independent CR and CRE detection, along with modules for signal processing and wireless communication. The differential method and system were validated in simulated blood, the detection error was reduced from 41.1% to 8.89% after applying the differential method, and the recoveries ranged from 89.5% to 107.8%, with errors remaining below 12%. This PEDOT:PSS/PBNPs hydrogel CRE biosensor, based on one-step modification method, offered a promising strategy for precise assessment of kidney and muscle health in both clinical and at-home settings.