2D/3D material amplification strategy for disposable label-free electrochemical immunosensor based on rGO-TEPA@Cu-MOFs@SiO2@AgNPs composites for NMP22 detection

Nuclear matrix protein 22 (NMP22) is a crucial bladder cancer marker, the accurate detection of which is conductive to improving the effectiveness of tumor prevention and treatment. However, due to low sensitivity, it is impossible for conventional immunoassay to detect the trace of NMP22 at the early stages of tumor progression. It is crucial to develop a simple, sensitive and accurate detection method of NMP22. As a variety of twodimensional (2D) material, reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) demonstrates excellent conductivity and contains abundant amino groups. As a sort of 3D material, silica-modified Cu-based metalorganic frameworks deposited silver nanoparticles (Cu-MOFs@SiO2@AgNPs) composites are characterized by large surface area, excellent biocompatibility and water stability, which allows the immobilization of antiNMP22 in large amounts via Ag-N bonds. Through a combination of the advantages exhibited by 2D material, 3D material, AgNPs and disposable screen-printed electrode, a disposable and sensitive label-free electrochemical immunosensor has been successfully assembled for NMP22 detection. In addition to exhibiting a wide linear range (0.1 pg center dot mL-1-1000 ng center dot mL-1) and a low detection limit (33.33 fg center dot mL-1, S/N = 3), the proposed immunosensor also demonstrated satisfactory selectivity, strong reproducibility and high stability. Moreover, the excellent performance in detecting human urine samples makes it applicable in practice.

Automated summary

A disposable and sensitive label-free electrochemical immunosensor has been successfully assembled for NMP22 detection, with a wide linear range, low detection limit, good selectivity, reproducibility, stability, and applicability in detecting human urine samples.