An electrochemical troponin I peptisensor using a triangular icicle-like gold nanostructure

Detection of troponin I (TnI), as a unique biomarker for myocardial infarction (MI), is highly important for diagnosis, prevention and therapy of MI, a major problem in the health policy and death. A triangular icicle-like gold nanostructure was firstly electrodeposited on a gold substrate to attain a high-surface area transducer, and characterized by field emission scanning electron microscopy. A 13-amino acid affinity peptide was then immobilized on the gold nanostructure surface to fabricate a TnI peptide-based biosensor, namely as peptisensor. The K3Fe(CN)(6)/K(4 )e(CN) 6 couple was applied as a redox marker to detect and quantify the TnI binding into the peptisensor surface. The times of peptide immobilization on the gold nanostructure and binding with TnI were optimized. Using the redox marker of ferro/ferricyanide and differential pulse voltammetry, we quantified TnI in a concentration range of 0.01-5 ng mL(-1) with a detection limit of 0.9 pg mL(-1). The fabrication reproducibility, stability over time and endurance of interfering effect of the peptisensor were evaluated. The peptisensor was finally applied for analysis of human serum samples.