Electrochemiluminescence immunoassay based on site-specific labeling using a histidine-binding iridium(III) solvento...

Area of Science:

• Inorganic Chemistry
• Analytical Chemistry
• Biomedical Engineering

Background:

• Histidine-bound bis-cyclometalated iridium (III) complexes are known luminophores.
• Electrochemical excitation of these complexes was previously uninvestigated.

Purpose of the Study:

• To demonstrate electrochemical excitation and electrogenerated chemiluminescence (ECL) of histidine-bound bis-cyclometalated iridium (III) complexes.
• To explore the application of these luminophores in novel ECL immunoassay methodologies.

Main Methods:

• Electrochemical excitation of iridium (III) complexes in homogeneous solutions and on magnetic beads.
• Development of a sandwich immunoassay concept utilizing site-specific antibody labeling.

Main Results:

• Successful electrochemical excitation and observation of ECL from iridium (III) complexes.
• Demonstration of ECL in both solution and on magnetic bead surfaces.
• Proof-of-concept for a sandwich immunoassay with site-specific labeling.

Conclusions:

• Histidine-bound bis-cyclometalated iridium (III) complexes are effective ECL emitters.
• Site-specific labeling and on-site signal generation offer a novel ECL immunoassay platform.
• The developed assay achieved a limit of detection <1 ng/mL for procalcitonin in human plasma.