Novel cloth-based closed bipolar solid-state electrochemiluminescence (CBP-SS-ECL) aptasensor for detecting carcinoembryonic antigen

This study involved the construction of a novel cloth-based CBP-SS-ECL aptasensor by introducing proximity hybridisation (PH) and solid-state electrochemiluminescence (SS-ECL) into a closed bipolar (CBP) electrochemistry system. Screen-printing was used to fabricate the cloth-based aptasensors, and PH and aptamers provided good selectivity for the sensor. Furthermore, the CBP-SS-ECL sensing interface was produced by immobilising of Ru(bpy)32+- doped silica nanoparticles (Ru-Si-NPs) on the anode of closed bipolar electrode (C-BPE). PH product (PP) was formed due to the target (carcinoembryonic antigen, CEA), and then the PP opened the Au NP-labelled capture probe (Au-CP) on the C-BPE anode (CBA), allowing ferrocene carboxylic acid (FcA) close to the CBA surface and Au NPs away from the surface. The corresponding quenching and enhancement of ECL signal by FcA and Au NPs, respectively, markedly enhanced ECL signal. This aptasensor successfully achieved quantitative detection of CEA, with a linear detection range of 5-100000 pg mL-1 and a detection limit of 1.6 pg mL-1. The described aptasensor showed an acceptable sensitivity, selectivity, stability, and ability to detect CEA levels in complex human serum samples. In particular, this aptasensor showed satisfactory versatility, indicating its potential for simultaneous detection of CEA and K-ras gene.