Specific Electrochemiluminescence of Aptamer‐Functionalized Quantum Dots with Lysozyme and Hemin as Co‐Triggers

This work proposed a label‐free, cost‐effective and fairly sensitive electrogenerated chemiluminescence (ECL) strategy for the specific detection of lysozyme based on the hemin/G‐quadruplex hybrid. Gold nanoparticles were spread onto the chitosan thin‐film as substrate to adsorb thiolated captures: a hairpin‐structured DNA, integrating dual head‐tail connected functional domains: one aptamer sequence for lysozyme and the other for hemin (iron(III) proto ‐porphyrin IX). In the presence of the both, the hairpin conformation unfolded and transformed into the hemin/G‐quadruplex motif, which quenched the ECL emission of underlaid quantum dots significantly via the consumption of dissolved oxygen as endogenous coreactant. This construction enabled a wide linear response to lysozyme, ranging from 20 pg·mL −1 to 5 µg·mL −1 , with a detection limit as low as 4.95 pg·mL −1 ( e.g. 9.4 pmol·L −1 ), demonstrating the prospective utilization of DNA technologies in bioanalysis.