Homogeneous electrogenerated chemiluminescencepeptide-based method for determination of troponin I

Abstract

A novel homogeneous electrogenerated chemiluminescence (ECL) peptide-based method for the determination of troponin I (TnI) was developed by using peptide (FYSHSFHENWPSK) as a molecular recognition element and ruthenium bis(2,2′-bipyridine) (2,2′-bipyridine-4,4′-dicarboxylic acid)-N-hydroxysuccinimide ester (Ru(bpy)₂(dcbpy)NHS) as an ECL label. Ru(bpy)₂(dcbpy)NHS was covalently labeled onto the peptide via acylation reaction and was utilized as an ECL probe. In the presence of TnI, a decrease in ECL signal was observed upon the binding event between peptide and target TnI. The ECL intensity versus the concentration of TnI was linear in the range from 7.8 × 10⁻¹⁰ g mL⁻¹ to 7.8 × 10⁻⁸ g mL⁻¹ with a detection limit of 1.2 × 10⁻¹⁰ g mL⁻¹. The relative standard deviation for 2.6 × 10⁻⁹ g mL⁻¹ was 3.8%. The proposed method has been applied to assay TnI in human control serum with satisfactory results. This work demonstrates that the combination of small peptide with a highly sensitive ECL technique for homogeneous ECL peptide-based bioassay is a great promising approach for simple, sensitive and selective determination of proteins.