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Fabrication of Tris(bipyridine)ruthenium(II)-Functionalized Metal–Organic Framework Thin Films by Electrochemically Assisted Self-Assembly Technique for Electrochemiluminescent Immunoassay

Qin, Xiaoli, Zhang, Xianhao, Wang, Minghan, Dong, Yifan, Liu, Junjie, Zhu, Zhiwei, Li, Meixian, Yang, Di, Shao, Yuanhua
Analytical chemistry 2018 v.90 no.19 pp. 11622-11628
Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, coordination polymers, detection limit, electrochemistry, electrodes, humans, image analysis, immunoassays, immunosensors, ligands, nitrates, protocols, ruthenium, scanning electron microscopy, zinc
A simple strategy for one-step fabrication of tris(bipyridine)ruthenium(II) (Ru(bpy)₃²⁺)-functionalized metal–organic framework (Ru-MOF) thin films using a self-assembly approach assisted by an electrochemical way was introduced. In this protocol, the electrochemically driven cooperative reaction of Ru(bpy)₃²⁺ as an electrochemiluminescent (ECL) probe and a structure-directing agent, trimesic acid (H₃btc) as a ligand, and Zn(NO₃)₂ as the Zn²⁺ source leads to an one-step and simultaneous synthesis and deposition of the MOF onto the electrode surface. Characterization of the Ru-MOF thin films was performed with scanning electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. Scanning ion conductance microscopy was specially applied in situ to image the topography and thickness of the Ru-MOF thin films. The Ru-MOF thin films as a sensing platform show excellent ECL behavior because of plenty of Ru(bpy)₃²⁺ molecules encapsulated in the frameworks. On the basis of the Ru-MOF modified electrodes, an ultrasensitive label-free ECL immunosensing method for the human heart-type fatty-acid-binding protein has been developed with a wide linear response range (150 fg mL–¹–150 ng mL–¹) and a very low limit of detection (2.6 fg mL–¹). The prepared immunosensor also displayed excellent stability and good specificity in the test of practical samples.