Research On The Design, Preparation And Application Of Nanophotochemical DNA Biosensors

The rapid development of biomedicine has put forward higher requirements for chemical analysis.High sensitivity,selectivity and throughput of biosensors are necessary for the detection of biomolecules and cells on microscopic scale.Therefore,combining the nano-materials with biosensors becomes an important mean of early diagnosis of cancer.It is a frontier in the fields of materials science and analytical chemistry to find functional nano-materials with excellent properties.Therefore,NaEuF4 nanoparticles,Au@Ag2S nanoparticles,MoS2 nanosheets and nitrogen doped carbon quantum dots were synthetized and involved into the construction of DNA biosensor.The aim results are as follows:1.NaEuF4/Au@Ag2S nanoparticles-based biosensor for ultrasensitive detection of DNA:The NaEuF4 nanoparticles(NaEuF4 NPs)and Au@Ag2S nanoparticles(Au@Ag2S NPs)were synthesized and characterized by transmission electron microscopy(TEM),fluorescence spectroscopy(FL)and ultraviolet-visible spectroscopy(UV-vis).The fluorescence resonance energy transfer(FRET)between NaEuF4 NPs and Au@Ag2S NPs was realized by applying NaEuF4 NPs as energy donor and Au@Ag2S NPs as energy receptor respectively.Finally,a molecular beacon DNA biosensor was constructed.The results showed that the detection range of the target DNA was 100 aM?100 pM,and the detection limit was 32 aM.At the same time,the sensor had good reproducibility,accuracy and anti-interference in the actual sample detection.2.MoS2 Nanosheets featured fluorescent aptasensor for multiple diagnosis of Cancer in Vitro and in Vivo:MoS2 nanosheets were prepared by a modified mixed solvent strategy for liquid exfoliation.The MoS2 nanosheets was characterized by TEM,X-ray diffraction spectrum(XRD),X-ray photoelectron spectroscopy(XPS)and Raman spectroscopy(Raman).MoS2 nanosheets exhibit a high fluorescence quenching ability to fluorescent dye,therefore,it was exploited as carrier and quencher for a fluorescent dye-labelled DNA aptamer(P0-FAM)to construct a biosensor.The results showed that the detection range of MUC1 in the solution was 1 nM?10 ?M and the detection limit was 25 pM.The detection range of MCF-7 was 103?5×105 cells/mL and the detection limit was 50 cells/mL,the biosensor also had the advantages of high sensitivity and specificity.3.Nitrogen-doped carbon dots-based biosensors for the detection of MUC1:First,the nitrogen-doped carbon dots with excellent fluorescence properties were prepared by hydrothermal method,and the PS@SiO2 microspheres were synthesized by Stober method,then the hollow SiO2 microspheres were prepared by calcination to remove the templates.The samples were characterized by TEM,FL,Fourier transform infrared spectroscopy(FT-IR)and so on.Next,the nanomaterials were assembled to construct a nitrogen-doped carbon dots-based biosensor.Finally,the biosensor was applied to detect the MUC1.The experimental results showed that the sensor had good stability,reliability and sensitivity.The detection range of MUC1 was 1 ?M?10?M,the detection limit was 10 nM,and the sensor could also be applied to cell imaging.