An ultrasensitive dual detection platform immunosensor based on glow-type carboxymethylated konjac glucomannan for detection of small cell lung Cancer marker NSE

In the field of biomedical detection, chemiluminescence (CL) immunosensors are valued for their high sensitivity, strong selectivity, and straightforward operation. Nonetheless, the majority of conventional CL immunosensors are flash-type, requiring large-scale instruments to capture CL signals, which restricts their use in point-of-care testing (POCT). In this work, konjac glucomannan (KGM) is firstly carboxymethylated to form CKGM, and chitosan (CS) is then connected through electrostatic interaction to obtain CKGM-CS hydrogel. Cu 2+ is subsequently loaded onto CKGM-CS hydrogel via coordination and electrostatic interactions. Luminol is finally encapsulated in CKGM-CS hydrogel by electrostatic interaction and adsorption. The obtained CKGM-CS@luminol/Cu 2+ exhibits a high density of “glow-type” CL emission. On this basis, an ultrasensitive label-free immunosensor was developed for the detection of neuron-specific enolase (NSE) by immobilizing specific antibodies, where the quantitation relies on the immunorecognition event directly modulating the CL signal. This dual-detection platform integrates a CL instrument with a smartphone. For the CL instrument, the linear range and limit of detection (LOD) of the established method are 0.1–1000 pg/mL and 0.027 pg/mL, respectively. For the smartphone, the linear range and LOD are 0.1–1000 pg/mL and 0.043 pg/mL, respectively. Ultimately, the technique can track NSE concentration in actual samples using two distinct capture approaches, offering a versatile method for developing sensitive, cost-effective, and simple dual detection platform label-free immunosensors for NSE detection. Moreover, employing a smartphone as a readout device simplifies the detection process, making it convenient for POCT and providing a novel approach for early small cell lung cancer (SCLC) diagnosis.