Previous researches have suggested the potential correlation between the development of breast cancer and the concentration of miRNA-21 in serum. Theoretically the doping of multivalent metal ions in WS2 could bring higher electron transfer capacity, but this hasn't been proven. To fill this research gap, through one-pot method we prepared seven nanocomposite structures modified with different metal ions (Co2+, Ni2+, Mn2+, Zn2+, Fe3+, Cr3+, La3+). Characterization revealed that ammonia produced by hydrothermal urea exfoliated the multilayer graphene oxide (MGO) and provided a nitrogen source for doping reduction to form a 3D flower-like structure (NrGOF) with high specific surface area. Meanwhile, the modification of WS2 by Fe3+ not only enhanced its electrochemical conductivity but also gave the material an additional peroxidase activity centre. In the composite Fe3+-WS2/NrGOF-AgNPs, NrGOF is used as a conductive loading interface for WS2, while Fe3+ served as the catalytic and electron transfer centre for secondary amplification of the electrochemical signal. The experimental results showed that the sensing platform has a low limit of detection (LOD) of 1.18 aM for miRNA-21 in the concentration range of 10-17-10-12 M and has been successfully applied to the detection of real serum samples.
Keywords: Biosensor; Fe(3+)-WS(2)/NrGOF; Metal ions screening; One-pot; miRNA-21.
Copyright © 2023 Elsevier B.V. All rights reserved.