Ultrasensitive detection of EGFR gene based on surface plasmon resonance enhanced electrochemiluminescence of CuZnInS quantum dots

In our work, a novel DNA electrochemiluminescence (ECL) sensor based on CuZnInS quantum dots (QDs) and gold-nanoparticles (Au NPs) is developed for highly sensitive detection of epidermal growth factor receptor (EGFR) Gene, which has a close relation with the lung cancer. The CuZnInS QDs work as a novel kind of ECL luminophore, whose defect state emission is suitable for ECL sensing. To enhance the sensitivity of the sensing system, Au NPs are utilized creatively to strengthen the ECL intensity of CuZnInS QDS according to the surface plasmon resonance (SPR) effect. An ultrasensitive and universal detecting platform is built based on the SPR effect between Au NPs and CuZnInS QDS. The effect of the capped stabilizer on the ECL signal of QDs is firstly investigated. Three different stabilizers are used to cap the CuZnInS QDs, including mercaptopropionic acid (MPA), l-glutathione (GSH) and cysteamine (CA). MPA capped CuZnInS QDs possess the strongest ECL intensity among the three kinds of the CuZnInS QDs. Under the optimum conditions, a good linear relationship between ECL intensity and the concentration of target DNA is obtained in the range from 0.05 nmol L-1 to 1 nmol L-1. The detection limit is 0.0043 nmol L-1. The proposed DNA sensor has been employed for the determination of target DNA EGFR in human serum samples with satisfactory results.