A Neuron-specific Enolase Electrochemical Immunosensor Based on rGO/Cu8Ni2 Nanocomposite with Enhanced Catalytic Activity

Abstract

Neuron-specific enolase (NSE) is a reliable biomarker for the diagnosis of small cell lung cancer (SCLC). Effective detection of NSE plays an important role in the clinical diagnosis, treatment, and prediction of disease recurrence of SCLC. Herein, a simple label-free electrochemical immunosensor based on reduced graphene oxide/Cu8Ni2 (rGO/Cu8Ni2) nanocomposite was reported to detect the neuron-specific enolase (NSE). The rGO/Cu8Ni2 nanocomposite was prepared by loading optimized CuNi (8:2) alloy on the reduced graphene oxide through electrostatic-adsorption interactions and in situ simultaneous reductions. As a noble-metal-free alloy, Cu8Ni2 exhibits favorable catalytic activity. Combining the CuNi alloys with graphene can effectively keep off the aggregation of the alloy and further maintain its high catalytic activity. Simultaneously with the huge surface area and conductivity of rGO, rGO/Cu8Ni2 showed increased bound antibodies and enhanced catalytic activity, which makes the fabricated immunosensor exhibit enhanced performance. Under the optimal conditions, the designed electrochemical immunosensor for detecting NSE showed a wide linear range from 500 fg ml−1 to 50 ng ml−1 and the low detection limit was 137 fg ml−1. The proposed immunosensor in this study provides an effective method for the detection of NSE and may be expected to be applied in clinical diagnosis and treatment.