Electrochemical Biosensor Based on Dual-Ligand Functionalized Lanthanide-Encapsulated Polyoxometalate Conductive Polymer Film for Detecting Broad-Spectrum Tumor Marker MicroRNA-155
Lina Meng, Xiaodan Jia, Zhigang Tang, Yalun Hu, Lijuan Chen, Junwei Zhao
Abstract
In this work, a dual-ligand functionalized lanthanide-encapsulated selenotungstate [H 2 N(CH 3 ) 2 ] 16 Na 2 H 10 [Ho 6 (H 2 O) 10 (HPACA) 4 W 10 O 28 (Ac) 2 ][SeW 9 O 33 ] 6 · 60H 2 O ( 1, HPACA = 2-pyrazinecarboxylic acid, HAc = acetic acid) was successfully acquired by simultaneously incorporating rigid HPACA and flexible Ac – ligands to one reaction system. Interestingly, the polyanion [Ho 6 (H 2 O) 10 (HPACA) 4 W 10 O 28 (Ac) 2 ][SeW 9 O 33 ] 6 28– of 1 is composed of six trivacant Keggin-type [B-α-SeW 9 O 33 ] 8– units interconnected through an organic–inorganic hybrid dual-ligand bimetallic [Ho 6 (H 2 O) 10 (HPACA) 4 W 10 O 28 (Ac) 2 ] 20+ cluster. Moreover, the 1 @PNMPy film (PNMPy = poly( N -methylpyrrole)) was successfully prepared through an electrochemical polymerization strategy. The doping of 1 significantly narrows the bandgap in the 1 @PNMPy film, which enables the 1 @PNMPy film to exhibit remarkable conductivity and rapid electron transfer capability. Then, the 1 @PNMPy film-modified glassy carbon electrode was used to construct a 1 @PNMPy-based electrochemical biosensor (ECBS), which achieves sensitive electrochemical detection (a low limit of detection of 0.108 fM and a wide concentration detection range of 10 –8 –10 –15 M) for broad-spectrum tumor marker microRNA-155. Also, the 1 @PNMPy-based ECBS has a good specific recognition performance for microRNA-155 in a variety of interfering media. The research not only contributes to a deeper understanding of the synthetic chemistry of multicomponent polyoxometalate (POM)-based materials but also can further expand innovative applications of multicomponent POM-based materials in electrochemical detection and electrochemical devices.