Electrochemical Detection of Biomarkers Via Affinity Binding with Functionalized Nanocomposite for Assessment of Tissue-Perfusion

Renin and lactate, although serving individually as indirect biomarkers of tissue perfusion, exhibit enhanced diagnostic and monitoring capabilities when utilized in combination for tissue perfusion assessment. To detect these biomarkers in human blood, we improved a screen-printed carbon electrode device by incorporating a nanocomposite film consisting of carbon nanotubes modified with gold nanostars (AuNSs). The developed nanocomposite films were used to modify the working electrodes, enhancing the surface area and the conductivity. Following morphological analysis and electrical characterization, these nanostructures were employed as the active layer atop the working electrode, facilitating the binding of receptors (renin antibody and lactate dehydrogenase) around the AuNSs. The serum samples containing different concentrations of renin (31.3–1000 pg/mL) and lactate (25–600 µM) were tested in the modified device with differential pulse voltammetry (DPV). The peak currents of the recorded curves were proportional to the concentrations of the biomarkers, with high coefficients of determination. Remarkably, the limit of detection values reached 4.84 µM, for lactate, and 0.7412 pg/mL, for renin. The proposed device had a strong agreement level with the gold-standard laboratory tests. Additionally, it was possible to detect both targets on the same device using the DPV method, offering a reliable and precise method for simultaneous biomarker detection in real-world applications.