Synthesis Of Carbon Nanohorns/Luminescent Particles Nanocomposites And Their Applications As Biological Label

As fluorescent label, compared with traditional organic fluorophores, quantum dots (QDs) and rare-earth doped upconversion luminescent nanoparticles (UCNPs) are more suitable for biological analysis and medical research due to their unique photophysical properties.Some problems in medical research especially cancer treatment are how to achieve the goals of drug targeting and fluorescence tracing simultaneously. QDs and UCNPs are the perfect biolabels for cell labelling and imaging. However, the lacking of drug storage space made it to be difficult to achieve the goal of drug targeting. After carbon nanotubes had been found by lijima in1991, the studies on carbon nanomaterials have made a tremendous progress. It was found that, compared with carbon nanotubes, single-walled carbon nanohorns (SWNHs) showed more advantages, such as higher purity, more reactivity sites, smaller size, and more space for drug storage. So that SWNHs have attracted much attention recently. However, carbon nanomaterials could not become fluorescent label due to their non-fluorescence. Therefore, it was the focus of attention to the composites of drug storage and fluorescence labeling. More and more scientists have been devoted to make the composites of carbon nanomaterials and fluorescent substances, for simultaneous fluorescence labeling and drug store. Based on our knowledge, up to now, there is nether about the composites of SWNHs/QDs nor SWNHs/UCNPs reported.In this work, the synthesis methods for two kinds of water-soluble fluorescent nanocomposites, combining thioglycolic acid (TGA) stabilized CdTe QDs with SWNHs and UCNPs with SWNHs via covalent bond were developed. And then the prepared two nanocomposites were used as label of live HeLa cells. The main contents are as follows:The ultraviolet light-assisted oxidation with hydrogen peroxide was proved to open the folding of carbon nanohorns effectively, and more importantly, created abundant oxygenated groups such as carboxylic groups to improve the water-soluble property.TGA stabilized CdTe QDs was synthesized by a hydrothermal method. In order to reduce fluorescence quenching and modify with amino groups, the QDs were combined with BSA. NaYF4:Yb,Er UCNPs were synthesized by a solvothermal method and coated with a thin layer of SiO2and further modified with amino groups through a typical Stober method. In the presense of EDC, the SWNHs/CdTe QDs and SWNHs/NaYF4:Yb,Er nanocomposites were prepared via the covalent combining of the carboxylic groups on SWNHs with the amino groups on the surface of QDs and UCNPs.The prepared SWNHs/CdTe QDs nanocomposites were covalently coupled with rabbit anti-CEA8antibodiy and then used successfully in the cell immunolabeling and imaging of live HeLa cells. The SWNHs/NaYF4:Yb,Er nanocomposites were covalently coupled with PEI (polyethyleneimine) and rabbit anti-CEA8antibodiy respectively, and then used successfully in the cell labeling and imaging of HeLa cells. It was observed that when the SWNHs/NaYF4:Yb,Er was modified with PEI, they were easy to be taken up by co-cultured HeLa cells via an endocytosis pathway. The new nanocomposites of SWNHs/CdTe QDs and SWNHs/NaYF4:Yb,Er showed good application potential in drug delivery and fluorescence tracing.