Palladium Nanoparticle-Decorated\nCopper-Hemin Metal\nOrganic Framework for Enzymatic Electrochemical Detection of Creatinine\nin Human Urine

Creatinine is indeed a crucial biomarker for kidney diseases.\nIn\nthis work, a novel electrochemical biosensor based on a copper-hemin\nmetal organic framework [Cu-hemin metal–organic framework (MOF)]\nnanoflake decorated with palladium (Pd) (Pd/Cu-hemin MOF) was fabricated\nand incorporated with creatinine deiminase (CD) on a glassy carbon\nelectrode (GCE) for creatinine detection. The formation of a Pd/Cu-hemin\nMOF composite was confirmed by X-ray photoelectron spectroscopy, X-ray\ndiffraction, and Fourier transform infrared spectroscopy. The formation\nof the composite as nanoflakes is evident from the scanning electron\nmicroscopy image. The transmission electron microscopy image clarifies\nthe decoration of palladium nanoparticles on Cu-hemin MOF surfaces.\nThus, the proposed biosensor (Pd/Cu-hemin MOF/CD/GCE) electrochemical\nperformances were studied with cyclic voltammetry, differential pulse\nvoltammetry, and electrochemical impedance spectroscopy. As a result,\nthe Pd/Cu-hemin MOF/CD/GCE-based electrochemical detection of creatinine\nexhibits a broad linear range from 0 to 130 μM (<i>R</i><sup>2</sup> = 0.99), a low limit of detection 0.08 μM, and\nan excellent sensitivity of 3.2 μA μM<sup>–1</sup> cm<sup>–2</sup>. The biosensor also determines creatinine\nin samples of human urine with a good recovery from 99.4 to 100.8%.\nThus, in this study, an electrochemical biosensing platform based\non Pd/Cu-hemin MOF/CD/GCE has been designed practically for creatinine.