A novel quantum dot nanocluster as versatile probe for electrochemiluminescence and electrochemical assays of DNA and cancer cells

• A novel PAMAM dendrimer/CdSe–CdS-QD signal probe was developed.
• Versatile ECL and electrochemical assays for DNA and cancer cells were proposed.
• Magnetic Fe3O4@Au nanoparticles were used for the convenient immobilization of cell aptamers.
• The present strategy could provide rapid and sensitive approaches for the accurate detection of DNA and cancer cells.

A novel dendritic quantum dot (QD) nanocluster was constructed and used as versatile electrochemiluminescence (ECL) and electrochemical probe for the detection of DNA and cancer cells. Owing to the many functional groups present in the nanoclusters, a large number of QDs were assembled on the nanoclusters, which could greatly amplify both the ECL and electrochemical signals of QDs. Carbon nanotubes (CNTs)/gold nanoparticles’ (NPs) hybrids were used as amplified platform for assembling large numbers of DNA on the electrode, which also improve the bioactivity and stability of the electrode. After the QD-DNA signal probe was recognized with target DNA (t-DNA), the amplified ECL signal for the detection of target DNA was obtained. Furthermore, magnetic nanoparticles were employed for cell aptamers immobilization, the same QD nanocluster-DNA probe was also extended for electrochemical detection of cancer cells using sensitive anodic stripping voltammetry (ASV) method, which simplified the separation procedures and improved the sensitivity. It is anticipated that the assays could provide promising and cost effective approach for the early and accurate detection of DNA and cancer cells.