Electrochemiluminescence immunosensor based on nanocomposite film of CdS quantum dots-carbon nanotubes combined with gold nanoparticles-chitosan

A novel and sensitive electrochemiluminescence (ECL) immunosensor based on CdS quantum dots (QDs)-carbon nanotubes (CNTs) and gold nanoparticles-chitosan (GNPs-CHIT) was presented. CdS QDs ECL was much enhanced by combing poly(diallyldimethylammonium chloride) functionalized CNTs. GNPs-CHIT nanohybrids was used to construct an effective antibody immobilization matrix with excellent stability and bioactivity. The principle of ECL detection for target human IgG is based on the increment of steric hindrance after immunoreaction, which resulted in the decrease in ECL intensity. The linear response range was between 0.006 and 150 ng mL−1, and the detection limit was 0.001 ng mL−1. This approach offers obvious advantages of being simpler, faster, and more stable compared with other immunosensors, which possesses great potential for protein detection in clinical laboratory.