Study On Electrochemiluminescence Analytical Methods Based On Quantum DOT Biological Probe And Signal Amplification Technique

In recent years, the research of nanomaterials is more and more deep, especially the quantum dots luminescent materials as nano-bioprobe has been widely used in every field. Electrochemiluminescence (ECL) has remarkable features such as simplicity, rapidity, high sensitivity and easy controllability. ECL biosensor has been extensively used for the detection of a wide variety of biomolecules. In this paper, we mainly studied the preparation of many quantum dots and composite nanomaterials, fabrication of quantum dotsbioprobe, and development of the ECL biosensor based on signal amplification, and achieved highly sensitive detection of cancer cells, thrombin, DNA and RNA.The major contents of our work were described as follows:1. In this work, we prepared a novel amplifiedECL signalprobebased on CdSe/ZnS QDs nanocluster by multibranched DNA hybridization chain reaction (HCR) on gold nanoparticles, and developed a sensitive ECL biosensor for detection of cancer cells. Firstly, a new gold nanorod-hematite nanostructure was used as magnetic nano-amplified platform to assemble abundant capture DNA (aptamer) on the magnetic electrode. Next, the probe DNA hybridized with the aptamers and initiated multibranched HCR on GNPs,thus numerous QDsnanoclustershowedhighly intense ECL signal. Finally, upon specific recognition of target cells to aptamers, the signal probes were released from the electrode, leading to a remarkable amplification of ECL signal change, which was used for sensitive detection of cancer cells.2. A novel water soluble dual-stabilizers-cappedCdSe quantum dot was synthesized, the quantum dots show excellent ECL and good stability. CdSe quantum dots were immobilized on the electrode by using PAMAM-CNT, and ECL quenching of CdSe quantum dots by gold nanoparticles was studied. A highly sensitive and selective ECL analytical method for the assay of thrombin was designed.3. Anovel PAMAM-Au nanocluster composite was synthesized, which was used to fabricate a new nanocluster-amplifiedquantum dots ECL bioprobe. In addition, a new sliver nanocluster with many reactive carboxyl groups was prepared, and used to assemble a large number of DNA molecules on the electrode. By using bifunctional DNA strand displacement reaction-mediated multiple cycling-amplification technique, an amplified ECL analytical method for detecting target miRNA was designed, and highly sensitive detection of miRNA was achieved.