An electrochemical immunoassay for neopterin was developed using recently produced specific antibodies immobilized to protein A-coated magnetic beads in combination with differential pulse voltammetry and screen-printed array of electrodes. Neopterin-alkaline phosphatase conjugate was used as label in a competitive assay format. Multiplexed analysis of neopterin was demonstrated by replacing the traditional ELISA with electrochemical detection and the traditional plastic wells with screen-printed array of electrodes. The optimized electrochemical method, based on polyclonal antibodies, reached a limit of detection of 0.008 ng/mL with an average RSD %=10. Serum samples collected from patients with sepsis, healthy volunteers and other patients without a confirmed clinical diagnosis were also analyzed. The obtained results, compared with those of a commercial ELISA kit, had a significant correlation, showing the possibility to distinguish among the serum samples from ill or healthy subjects.
Keywords: Electrochemical immunoassay; Magnetic beads; Neopterin; Screen-printed arrays; Serum samples.
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