A Novel Redox-free Immunosensor Concept Based on Cobalt Phthalocyanine@carbon Nanotubes Pseudocapacitor for Cardiac B-type Natriuretic Peptide Detection

B-type natriuretic peptide (BNP) is a selective biomarker for cardiac diagnosis and prognosis of patients with cardiac insufficiency or heart failure, which means the pump function of cardiac muscle is reduced. A pseudocapacitive immunosensor was developed based on faradaic currents generated by a reduction-reaction with a metallocyanine modified-carbon nanotube surface. This technique is based on changes in interface by antigen-antibody interactions, which perturbs the dependent-diffusion potential reducing the charge transfers proportionally to the BNP captured. This new concept allows new perspectives for point-of-care tests since it is simpler and faster to manage with direct measurements of samples than conventional immunosensors.