Design of an electrochemical hydrogel nanocomposite immunosensor for the detection of hemoglobin in blood

A novel hybrid hydrogel nanocomposite immunosensor was developed for the electrochemical detection of hemoglobin in blood. The transducing element was based on carbon black (CB)-nanomodified screen-printed electrodes (SPEs) on which a poly(ethylene glycol)-diacrylate hydrogel (PEGDA) doped with gold nanoparticles (AuNPs) was photopolymerized in situ. The fabricated PEGDA-AuNPs/CB-SPEs were then functionalized with oriented anti-hemoglobin antibodies. The immunosensor was analyzed by Electrochemical Impedance Spectroscopy (EIS) and Differential Pulse Voltammetry (DPV) at different modification steps, while its morphology was evaluated by Scanning Electron Microscopy (SEM). The analytical performances of the resulting PEGDA-AuNPs/CB-SPE immunosensor were assessed by DPV analysis, demonstrating the ability of the proposed system to detect hemoglobin in both standard solution and serum samples with a limit of detection (LOD) of 0.005 mg/mL within a dynamic response in a concentration range from 0.005 to 0.1 mg/mL. Slight interference was observed in the presence of glucose and ascorbic acid at concentrations much higher than those physiologically present in the blood. Moreover, any matrix effect was evidenced in serum samples, with a good recovery value of 107 ± 4 % obtained for a hemoglobin concentration of 0.025 mg/mL.