Luminol-based ternary electrochemiluminescence nanospheres as signal tags and target-triggered strand displacement reaction as signal amplification for highly sensitive detection of Helicobacter pylori DNA

Herein, a novel ternary electrochemiluminescence (ECL) nanosphere containing the emitter of luminol (Lum), the coreactant of polyethylenimine (PEI) and the coreaction accelerator of amino-terminated perylene derivative (PTC-NH2) was prepared for the first time, which possessed strong ECL emission due to intramolecular coreaction of self-enhanced PEI-Lum and intermolecular coreaction acceleration of PTC-NH2 to Lum/H2O2 system. Combining the Lum-based ternary ECL nanosphere with target-triggered strand displacement reaction, a highly sensitive and enzyme-free biosensor was constructed for determination of Helicobacter pylori DNA. This developed ECL biosensing method exhibited a wide linear range from 10 fM to 10 nM and a detection limit down to 2.4 fM for Helicobacter pylori DNA detection. Therefore, this work provides a new avenue to develop high-performance ECL nanomaterials and an enzyme-free bioassay to be applied in the clinical molecular diagnosis of gastric diseases.