DNA tetrahedral nanostructures-loaded DNA microcapsule-enhanced catalytic hairpin assembly for electrochemiluminescence detection of serotonin.

Serotonin is a crucial neurotransmitter, with its levels being particularly significant for life safety. Here, a self-quenching electrochemiluminescence (ECL) biosensor was designed for serotonin assay based on DNA tetrahedral nanostructures (DTNs)-enhanced catalytic hairpin assembly (CHA). In this work, stimuli-responsive serotonin aptamer-cross-linked DNA-stabilized microcapsules loaded with DTNs were presented. The presence of serotonin effectively controlled the release of abundant DTNs, achieving enzyme-free signal amplification and transduction. Specifically, DTNs featuring a rigid 3D framework and multi-sites exhibited high collision efficiency, thereby achieving a high reaction efficiency of CHA. On the basis of ECL resonance energy transfer (ECL-RET), the ECL emission of CdS QDs was quenched by proximal Au nanoparticles (Au NPs). The proposed sensor showed excellent performance in self-quenching detection of serotonin ranging from 1.0 pM to 1.0 μM with a low detection limit of 0.3 pM. Moreover, satisfactory results were obtained while detecting serotonin in human serum and cell lysate samples. Overall, the proposed method presented a promising and straightforward platform for the trace detection of serotonin.