Study On Preparation And Spectral Properties Of Quantum Dots-Fluorescent Dye As Biological Complex Probe And Breast Cancer Cell Labeling

Cancer is a disease threaten human healthy severely, therefore, early detection,early diagnosis are more important significance to the targeted recognition of solidtumor. In tumor recognition technology, the fluorescent probe biological labeling haveattracted more and more attention in detection and treatment of tumor, due to itsunique advantages, such as fast detection speed, high sensitivity, safety and accuracy,good repetitiveness and so on.Fluorescent dye and nanocrystals quantum dots (QDs), usually used asfluorescent probe in biological labeling. Fluorescent dye possesses many distinctiveproperties: it has very high molar absorption coefficient, high fluorescence quantumefficiency, and good chemical stabilities, and colloidal semiconductor QDs have manyunique advantages, such as broad fluorescence spectrum, good biocompatibility, goodphotostability, strong fluorescence and so on. If combine advantages bothnanocrystals QDs and fluorescent dye, which become complex fluorescent probe, canimproved interaction and information communication between fluorescent probe andbiological tissue. For this reason, the following areas were studied in this presentpaper:(1)Three nanocrystals QDs, include CdTe, CdTe/CdS core/shell structure,CdTe/CdS/ZnS core/shell/shell structure were prepared by aqueous phase one-potsynthesis, the products structure were characterized and the spectral properties wererevealed. The results were shown that the absorbance wavelength of them situated at494-530nm, and the emission wavelength of them situated at550-602nm.(2)Embedded fluorescenct dye is often used as biological labeling because ofhigh molar absorption coefficient, high fluorescent quantum yield, and so on.Carbazole ring has a special planar rigid structure and conjugated system, to introducecarbazole ring into structure of fluorescent dye can increase the conjugation of systemand interaction of π electron, result in the emission wavelength of fluorescent probebathochromic shifted, Stokes shift increased. In order to keep the embedded features,this paper selected the benzooxazole, benzothiazole, quinoline and indole ringstructure unit of three commonly used oxazole yellow (YO), thiazole orange (TO) andcyanine dye (Cy3), which can be combined with carbazole ring, indolo [3,2-b]carbazole ring, designed and synthesized several novel styryl fluorescent dyes containcarbazole group, the compounds structure were characterized and the spectral properties were revealed. The results were shown that the absorbance wavelength ofthem situated at489-512nm, and the emission wavelength of them situated at600nm.(3)A new complex fluorescent probe of CdTe/CdS core/shell structure quantumdots-fluorescent dye were synthesized by chemical bonding, the compounds structurewere characterized and the law of charge transfer quenching between quantum dotsand fluorescent dye were preliminarily revealed.(4)Fluorescent dyes were modified by chitosan (CTS) and folate in order toenhance the biocompatibility and targeting, and the spectral properties of modifiedfluorescent probe were studied. Used TO and new styryl fluorescent dyes, both ofthem were modified by folate or CTS. They were used for targeted label breast cancerMCF-7cells and flow cytometry analysis, and to observed specific recognition ofbreast cancer MCF-7cells. The results was shown that the modified fluorescent probecould selectively targeted folate receptor over-expressed tumors according to theMCF-7cells and in vivo fluorescence imaging performed on nude mouse with breastcancer.