A sandwich-configuration ratiometric electrochemical immunosensor based on dual signal amplification of NH2-GO/Fe-Ni@Ti0033C2Tx/NH2-GO/Fc@AuNPs and BPNPs/AuPt-MB for the detection of survivin

Survivin serves as a crucial biomarker for bladder cancer, so exploring the detection method is essential. Therefore, a sensitive ratiometric electrochemical immunosensor was developed. In brief, a double-layered amino graphene oxide (NH 2 -GO) sandwich enhanced by Fe-Ni@Ti 3 C 2 T x (NH 2 -GO/Fe-Ni@Ti 3 C 2 T x /NH 2 -GO) significantly amplified the detection signal. ferrocene@Au nanoparticles (Fc@AuNPs) provided a reference signal, and Ab 1 was anchored via an Au-N bond. Moreover, AuPt-methylene blue (AuPt-MB) served not only as a secondary signal but also anchored Ab 2 through Au-NH 2 and Pt-NH 2 bonds. Black phosphorus nanoplates (BPNPs) improved conductivity and provided additional binding sites for AuPt-MB. The immunosensor exhibited a broad detection range (0.001~1000   ng/mL) and a low detection limit (0.00065   ng/mL), facilitating successful survivin detection in human urine samples with promising clinical analysis applications.