Electrochemical signal amplification strategy based on trace metal ion modified WS2 for ultra-sensitive detection of miRNA-21
Sinan Fu, Chang Xie, Zhiruo Yang, Mingdi Jiang, Jing Cheng, Chengliang Zhu, Kailang Wu, Huarong Ye, Wei Xia, Nicole Jaffrézic‐Renault, Zhenzhong Guo
Abstract
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 WS 2 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 (Co 2+ , Ni 2+ , Mn 2+ , Zn 2+ , Fe 3+ , Cr 3+ , La 3+ ). 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 WS 2 by Fe 3+ not only enhanced its electrochemical conductivity but also gave the material an additional peroxidase activity centre. In the composite Fe 3+ -WS 2 /NrGOF-AgNPs, NrGOF is used as a conductive loading interface for WS 2 , while Fe 3+ 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.