The Synthesis Of New Type Of Nucleic Acid Fluorescent Probe And Its Application In Biosensors

Biosensors receive extensive attention of researchers because of the advantages of low detection limit,wide linear range and so forth,While nucleic acid fluorescent probe has many advantages,such as easy to synthesis,good selectivity,good stability and so on.In this paper,combining those advantages of nucleic acid fluorescent probe and biosensor,three different biosensors with high sensibility have been established.Four parts are referred in the article.In chapter 1,the definition and kinds of the biosensor were primitively referred;the fluorescence technology was described,too.Moreover,the application of some probes was also outlined.Then the purpose and contents of this research were pointed out.In chapter 2,the synthesis of a new styryl derivative nucleic acid fluorescent probe N-methyl-2,6-2(4-styrene dimethylamino)pyridine(DMA)was accomplished.DNA could enhance the fluorescence of DMA,based on the above phenomenon,a biosensor of thrombin determination was established.Briefly,thrombin could combine with the aptamer to form the G-DNA,which could stop the exonuclease I to hydrolysis DNA,nucleic acid fluorescent probe DMA could combine with G-DNA to achieve a strong fluorescence.On a bisis of this method,the detection limit was 22.2 nM.The fluorescence intensity and the concentration of thrombin had a linearity in the range of 0.1-20.0 ?M.The proposed biosensor had been applied to detect serum with satisfactory results.In chapter 3,a new type of styryl derivatives nucleic acid fluorescent probe 2-indole-3-ethylene-4-(2-quinoline-1-methyl)iodine(E36)was synthesized.DNA could increase the fluorescence of E36,based on above phenomenon,an biosensor of biotin detection had been set up.When biotin was present,free biotin and ssDNA which was modified by biotin could compete for streptavidin to result in part of ssDNA not protected by streptavidin,which could be hydrolysised by the exonuclease I.Nucleic acid fluorescent probe E36 could not combine with the hydrolysised DNA to achieve a weak fluorescence.The fluorescence intensity has a linearity with the logarithm of biotin concentration in the range of 70.0 pM-400.0 nM with a detection limit of 0.03 nM(S/N=3).In chapter 4,a label free fluorescent biosensor had been established to detect RNA on account of nucleic acid fluorescent probe E36.Furthermore,the way to combine with RNA was discussed.The enhanced fluorescent intensity of the system had a linaer relationship with RNA concentration in the range of 0.2 ?g/mL-80.0?g/mL with a detection limit of 0.044 ?g/mL(S/N=3).The interaction mechanism for the binding of E36 to RNA was studied in detail,which implied that the interaction mode between E36 and RNA were electrostatic bonding and groove binding,part was intercalation binding,which made the E36-RNA more stable.