A label-free electrochemical immunosensor based on PdPtCu@BP bilayer nanosheets for point-of-care kidney injury molecule-1 testing

Kidney injury molecule-1 (KIM-1) protein is a vital biomarker for the early diagnosis of acute kidney injury (AKI). Therefore, a rapid and sensitive method for KIM-1 detection is urgently needed. Herein, a novel label-free electrochemical immunosensor constructed on [email protected] phosphorus (BP) bilayer nanosheets (BNSs) is reported for point-of-care (POC) testing of KIM-1. Monolayer-monolayer [email protected] BNSs, a novel signal substrate, were successfully synthesized using BP nanosheets combined with trimetal PdPtCu nanosheets. Benefiting from the excellent conductivity and peroxidase-like performance of [email protected] BNSs, the designed label-free electrochemical immunosensor exhibited exceptional detection properties. Under optimal conditions, the facile immunosensor displayed satisfactory linearity from 100 pg/mL to 100 ng/mL with a minimum detection limit of 32 pg/mL. Moreover, it takes 60 min from target addition to measurement completion. Meanwhile, the developed sensing strategy was successfully applied to specifically detect KIM-1 in real samples. The proposed strategy enables rapid and sensitive protein assays, providing a potential versatile platform for POC testing.