Polymer matrices with molecular memory as affine adsorbents for the determination of myoglobin as a cardiac marker of acute myocardial infarction by voltammetry

Resumo

A possibility of myoglobin determination using screen-printed graphite electrodes modified with a poly(o-phenylenediamine)-based molecularly imprinted polymer (MIP) obtained by the electropolymerization of o-phenylenediamine monomer molecules on the surface of a screen-printed graphite electrode in the presence of myoglobin template molecules is considered. It is shown that the conjugation of MIP with multiwall carbon nanotubes (MWCNT) results in an increase in the sensitivity of the MIP-biosensor in the electrochemical determination of myoglobin by the direct registration of the reduction peak of hemoprotein Fe³⁺ by square wave voltammetry on screen-printed graphite electrodes modified with MWCNT/MIP and MIP. Equilibrium dissociation constants K_d for the interaction of myoglobin with MWCNT/MIP- and MIP-electrodes, which equaled (9.8 ± 2.6) × 10^–11 and (2.4 ± 0.5) × 10^–8 M, respectively, are calculated. It is shown that the sensitivity of the electrochemical MWCNT/MIP-biosensor for myoglobin determination (1.5 × 10^–2 A/nmol of myoglobin) is higher than that of the MIP-biosensor (2.0 × 10^–4 A/nmol of myoglobin).