The Construction Of Molecular Beacon With CdSe Quantum Dots For The Detection Of Telomerase And Its Performance Studies

Human telomerase reverse transcriptase gene(hTERT)was expressed specifically at high level only in tumors.So,in this study,a novel molecular beacon using CdSe quantum dots as fluorescent donors and based on the fluorescence resonance energy transfer system would be developed for detecting hTERT-mRNA expression,which was used to detect whether the cell undergo cancerization in a rapid way.It mainly contained 3 parts as follows:First,the synthesis of CdSe QDs and its optical properties.In this study,water-soluble CdSe QDs was obtained by one-pot synthesis method.The synthesized CdSe QDs were uniformly dispersed in water with a maximum absorbance at 380 nm and a 6500 fluorescence intensity at 550 nm excitation,meanwhile the stocks-shift was 170 nm.With the pH rising,the fluorescence intensity was getting higher,but lower when temperature went up.The experiments showed the concentration of TGA and ageing temperature would influence the size affection,generating defect emission based on different structures.Different concentrations of TGA would not affect the absorbance spectrum,but the fluorescence spectrum got blue-shift from 570 nm while the concentration increasing.And the absorbance and fluorescence spectrum both blue shifted while the ageing temperature getting higher.Second,the toxicity study of Cd material QDs to KM mouse.The KM mice were fed by water,CdSe QDs solutions and CdSe-ZnS QDs solutions separately.The mice in CdSe QDs group and CdSe-ZnS QDs group were a little sluggish with hair slightly erecting,but breathing evenly,defecating and eating normally.The results showed Cd material QDs would influence the mice a little bit but generally no toxicity.The fluorescent slices of mouse blood displayed CdSe QDs could enter the mouse blood cells and showed blood cells of mice round and full,in good condition,slightly uneven distribution,but does not affect the overall observation.The results of red blood cells and white blood cells counting showed that in the group of CdSe QDs the number obviously below the normal range,but the CdSe-ZnS QDs group was close to the control group.Third,the construction of molecular beacon named CdSe QDs-DNA-Dabcly and the analysis of its optical properties.The molecular beacon was synthesized by a carboxyl modified CdSe QDs and an amino modified single-strand DNA.The fluorescence intensity of CdSe QDs,CdSe QDs-ssDNA molecular beacon and the conjugation of MB and target DNA were measured respectively.The results showed because of the FRET the fluorescence intensity ofCdSe QDs-ssDNA molecular beacon was lower than CdSe QDs,however,the fluorescence intensity recovered after attached to the target DNA.