Homogeneous electrogenerated chemiluminescence peptide-based method for determination of troponin I

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.