Synthesis and Structural Optimization of Iridium(III) Solvent Complex for Electrochemiluminescence Labeling of Histidine-Rich Protein and Immunoassay Applications for CRP Detection
Yuyang Zhou, Yangming Ding, Yinhao Huang, Leilei Cai, Jiawei Xu, Xiao Ma
Abstract
N bidentate main ligands have been designed and synthesized in this work. Bovine serum albumin (BSA) as the standard histidine-rich protein is initially employed to evaluate the labeling performances by comparing the ECL intensity of the same amount of BSA labeled by different iridium(III) solvent complexes. Importantly, a magnetic beads-based sandwich immunoassay platform using Ir-dmpq (iridium(III) acetonitrile complex with 2-(3,5-dimethylphenyl)quinoline as the main ligand) as a structurally optimized labeling agent has been successfully constructed to detect C-reactive protein (CRP, an important biomarker of systemic inflammation in clinic), and the limit of detection based on this novel labeling agent could reach below 1 ng/mL, which may further pave the way for applications of the iridium(III) solvent complex in histidine-rich protein ECL labeling beyond fluorescence labeling.