Electrochemical immunosensor for detecting typical bladder cancer biomarker based on reduced graphene oxide–tetraethylene pentamine and trimetallic AuPdPt nanoparticles

•GO–TEPA not only has the same property as rGO but also promote its water solubility.•AuPdPt NPs were used to immobilize antibodies and accelerate electron transfer.•Label-free immunoreactions are used to detect nuclear matrix protein 22.

A highly sensitive electrochemical immunosensor for detection of typical bladder cancer biomarker-nuclear matrix protein 22 (NMP22) was developed by using reduced graphene oxide–tetraethylene pentamine (rGO–TEPA) and trimetallic AuPdPt nanoparticles (NPs). rGO–TEPA was used as the ideal material for signal amplification and AuPdPt NPs immobilization due to its excellent conductivity and large surface area. An effective platform was constructed for antibodies anchoring by using AuPdPt NPs, which kept the antibodies’ high stability and bioactivity. Moreover, AuPdPt NPs could accelerate the electron transfer and enhance the signal response, which assisted by the synergistic effect of the three different metals (Au, Pd and Pt). The proposed immunosensor showed satisfied performance such as simple fabrication, low detection limits (0.01 U/mL), wide linear range (from 0.040 to 20 U/mL), short analysis time (2 min), high stability and selectivity in the detection of NMP22. Furthermore, the proposed immunosensor was employed to test real urine samples with satisfactory results.

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