An enzyme-free electrochemical immunosensor based on quaternary metallic/nonmetallic PdPtBP alloy mesoporous nanoparticles/MXene and conductive CuCl2 nanowires for ultrasensitive assay of kidney injury molecule-1

Herein, a novel enzyme-free electrochemical immunosensor based on quaternary metallic/nonmetallic PdPtBP alloy mesoporous nanoparticles (MNPs)/MXenes and CuCl2 nanowires (NWs) is reported for detection of kidney injury molecule-1 (KIM-1). PdPtBP MNPs/MXene nanocomposites, the novel signal amplification labels, were successfully synthesized using MXenes with the large surface area and the quaternary PdPtBP MNPs nanozymes with outstanding peroxidase-like catalytic activity. Meanwhile, the combination of high conductive CuCl2 NWs with superior biocompatible gold nanoparticles (AuNPs) is introduced as the substrate to modify the glassy carbon electrode (GCE). Benefiting from the excellent electrochemical performances of PdPtBP MNPs/MXene and CuCl2 NWs, the sandwich-type electrochemical immunosensor showed outstanding analytical performance in the presence of hydrogen peroxide (H2O2). Under the optimized conditions, the electrochemical immunosensor exhibited a good linear response from 0.5 ng/mL to 100 ng/mL with a detection limit of 86 pg/mL. Additionally, the established immunosensing method was successfully applied for the specific detection of KIM-1 in the urine. Thus, the enzyme-free electrochemical immunosensor provides a promising prospect for the detection of KIM-1 in the field of clinical diagnostics.