Synthesis Of Near-infrared-emitting Quantum Dots And Their Application In Electrochemiluminescence Immunosensing

Quantum dots (QDs) with excellent luminescent properties and good biocompatabilities have been extensively applied in biolabel and biosensing. QDs with near-infrared (NIR) emission are particularly attractive, as biological autofluorescence and tissue absorption are both at their minima in this wavelength range. Electrochemiluminescence (ECL) exhibit the merits of both luminescence and electrochemistry analysis, and have been extensively employed in biosensors. Quantum dots are considered one of the three main kinds of electrochemiluminescence luminophores due to their unique properties. Thus, synthesizing NIR-emitting quantum dots with ECL activity and developing novel quantum dots based ECL immunosensors will be of great significance for the development of life science.Thus, based on the current developments of QDs in our group, we explored the synthesis of NIR-emitting quantum dots and their application in ECL immunosensing. The major contents were described as follows:1. Microwave-assisted synthesis of highly luminescent near-infrared emitting CdSeTe/CdS/ZnS quantum dots With the precise controlment of lattice mismatch, we synthesized small CdSeTe nanoclusters at low temperature, and then further synthesized green-to near-infrared-emitting CdSeTe/CdS quantum dots in one-pot with the assistance of microwave irradiation, which showed small diameters and good optical properties. After coated the CdSeTe/CdS quantum dots with ZnS shell through epitaxial growth, the obtained CdSeTe/CdS/ZnS quantum dots showed better optical properties and good biocompatibility.2. Electrochemiluminescence energytransfer-promoted ultrasensitive immuno-assay using near-infrared-emitting CdSeTe/CdS/ZnS quantum dots and gold nanorodsThe CdSeTe/CdS/ZnS QDs are used for the fabrication of a novel ECL-ET based immunosensor for the detection of carcinoembryonic antigen (CEA). Taking advantage of the inherent energy tunable properties of both QDs and gold nanorods (GNRs), perfectly energy matched CdSeTe/CdS/ZnS QDs and GNRs were selected and used as the donor/acceptor pair for the fabrication of ECL-ET based immunosensor. Greatly improved sensitivity was realized in this work via twofold signal amplification from mCNTs-QDs nanocomposites and ECL-ET technology. CEA in human serum was measured with this sensor with high accuracy in comparison with a referee ELISA method. It provided a novel class of signal amplification strategy for ECL immunosensing, and can be adopted easily for the detection of other proteins.