One-Step Electrochemical\nModification of PEDOT:PSS/PBNPs\nHybrid Hydrogel on the Screen-Printed Electrode Surface for Highly\nSensitive Detection of Creatinine

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