Synthesies Of Near-infrared Quantum Dots And Their Bioapplication

Quantum dots (QDs) have drawn significant attention due to their unique properties-high quantum yields, narrow emission spectra and high photobleaching resistance. These advantages endow QDs the ability as a promising tool in optoelectronics, solar cells and biological sensors. Near-infrared emission QDs are promising tools in biological analytic, because of its minimized biological autofluorescence and increased penetration of emission light through tissues in the NIR window However, most available QDs are composed of known toxic elements such as Cd, Pb, As, etc. The safety of QDs biological labels maintains a major obstacle in their future biomedical exploration. It will decrease the cototoxicity by modifying the QDs and the surface defect at the same time. Based on the recent development, we explored synthesis of highly luminescent and low cytotoxicity QDs for targeted cell imaging and immune sensor. The major results are summarized as followed:1. Highly luminescent and biocompatible near-infrared core-shell CdSeTe/CdS/C quantum dots for probe labeling tumor cellsNear-infrared (NIR,650-900 nm) fluorescent quantum dots are highly promising as NIR bioprobes for high-resolution and high-sensitivity bioimaging applications. In this study, double shelled NIR CdSeTe/CdS/C quantum dots (QDs) were synthesized for the first time by a liquid phase synthesis method. The resulted QDs were characterized by UV-VIS spectra, Fluorenscence Spectra, HRTEM, FTIR, XRD and XPS. On account of the formation of carbon shell, the prepared QDs showed low cytotoxicity and good biocompatibility which is confirmed by MTT assay. The imaging of targeted Human cervical carcinoma cells (HeLa cells) indicated that CdSeTe/CdS/C QDs owned excellent optical properties and cell viability. These results clearly demonstrated that CdSeTe/CdS/C QDs could be a promising candidate for further bioapplications.2. Electrochemiluminescence of CdSeTe/CdS/C QDs and graphite oxide PANi hybride and the application in immunoassayECL emission of CdSeTe/CdS/C QDs and graphene oxide -polyaniline nanowires/QDs was studied. ECL of CdSeTe/CdS/C enhanced siginificantly by combining the graphene oxide -polyaniline nanowires. In this work, we developed an immunosenor for carcinoembrynic antigen (CEA) detection. The immunosensor had a sensitive response to CEA in the range from 0.1 pg·mL-1 to 10 ng·mL-1 with the detection limit of 0.05 pg·mL-1. The results showed that the ECL immusensor provised a promising application for the detection of CEA.