CePO4/CeO2 heterostructure and enzymatic action of D-Fe2O3 co-amplify luminol-based electrochemiluminescence immunosensor for NSE detection

Abstract

The construction of advanced systems that can accurately detect neuron-specific enolase (NSE) is critical to the rapid diagnosis of small cell lung cancer (SCLC). Herein, a luminol-based electrochemiluminescence (ECL) biosensor enhanced by reactive oxygen species (ROS) is proposed to perform the ultrasensitive detection of NSE. D-Fe2O3@Pt, synthesized as a signal indicator, was combined with luminol to significantly shorten its electron transfer pathway. Its peroxidase activity catalyzed the decomposition of H2O2 to generate a large amount of •OH, thus considerably increasing the ECL signal of the luminol–H2O2 system. CePO4/CeO2 heterostructures with improved surface-active areas were then employed as sensing substrates. The platform enabled the accelerated generation of O2•− through enriched Ce4+/Ce3+ redox pairs, thereby amplifying the strength of the response of the foundation. Through integrated dual ROS amplification, the proposed sandwich ECL immunosensor configuration achieved sensitive detection in the detection range of 76 fg/mL – 100 ng/mL, with a detection limit of 72.4 fg/mL. Furthermore, the sensor exhibited high selectivity for the determination of NSE in human serum. Overall, this study serves as an important reference for integrating ROS and enzymatic strategies in ECL research to achieve accurate, sensitive, and highly selective detection of a target.