Ultrasensitive NSE detection by multisegmental nanowire modified immunosensor

In this study, we present the development of a highly sensitive electrochemical immunosensor for the detection of neuron-specific enolase (NSE). NSE is a critical biomarker in the diagnosis of small cell lung cancer. The sensor is composed of multi-segmented nanowires (Ni/PANI/Au) that are synthesized via sequential electrochemical deposition within a polycarbonate template. The nanowires are characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses. The nanowires were subjected to functionalization with antiNSE antibodies, employing 11-mercaptoundecanoic acid (MUA), 6-mercapto-1-hexanol (MCH), and EDC-NHS chemistry. The bioconjugated nanowires were immobilized on screen-printed carbon electrodes (SPEs). Subsequently, the nanowires underwent treatment with BSA and Nafion. This treatment blocked nonspecific sites and improved stability. The present study employed electrochemical impedance spectroscopy (EIS) to facilitate the analysis of signal transduction. The immunosensor demonstrated a linear detection range of 20-2500 fg/mL, exhibiting an ultra-low limit of detection (LOD) of 0.461 fg/mL. The assay exhibited excellent reproducibility, with a relative standard deviation (RSD) of less than 5 %. It demonstrated selectivity against common interferents, including CA125, CEA, HIgG and HSA. Additionally, it demonstrated regeneration capacity, with the ability to undergo up to 13 cycles, and it exhibited storage stability, maintaining its integrity for over 60 days when stored at 4 degrees C. The assay demonstrated high sensitivity and reliability when evaluated using spiked serum samples. In comparison with conventional detection platforms, such as ELISA and commercial NSE kits, the immunosensor under consideration offers superior detection limits, operational simplicity, faster analysis time, and cost-efficiency. These attributes underscore their potential in clinical diagnostics.