To investigate the feasibility of DNA fluorescence capillary biosensor labeled with Cy5,based on fluorescence capillary analysis(FCA),the DNA biosensor using capillary as immobilization and detection carrier of DNA probe(20-mer-ssDNA) were immobilized on the inner wall of capillary by poly-l-lysine to make DNA fluorescence capillary biosensor(DNA-FCB).The DNA-FCB was hybridized with complementary target DNA labeled by Cy5.The target DNA was qualified or quantified by detecting the fluorescent density of the Cy5 using F-4500 spectrofluorometer.The results showed that the concentration of the target DNA had good linearity with the fluorescent intensity in range of 0.2～1.2μmol/L when sample volume was 5μL.RSD was lower than 3.5%.The concentration detection limit of the target DNA was 0.39μmol/L.The DNA-FCB can be used to qualify or quantify the target DNA.DNA-FCB is simple with advantages of lower sample and reagent volumes,repeated use of capillary,the lowest test cost,and reduce the pollution to environment.

Goldview marked DNA fluorescence capillary biosensor was studied in the present paper. Based on fluorescence capillary analysis (FCA), the DNA biosensor uses capillary as immobilization carrier and detection carrier of DNA probe. Probes (20-mer-ssDNA) were immobilized on the inner wall of capillary by poly-l-lysine, and DNA fluorescence capillary biosensor (DNA-FCB) was made. After being hybridized with complementary target DNA and dyed by Goldview, the target DNA was qualified or quantified by detecting the fluorescence density of the Goldview using F-4500 spectrofluorometer. The sample volume was 12 microL. The concentration of the target DNA showed good linearity with the fluorescence intensity in the range of 0. 4-4 micromol x L(-1) (2.4-24 mg x L(-1)) (y = 65.911x + 3.9944, r = 0.9989). The RSD was lower than 3.5%. The concentration detection limit of the target DNA was 0.39 micromol x L(-1) (2.2 mg x L(-1)). The DNA-FCB can be used to qualify or quantify the target DNA. It's advantages are simplicity of manipulation, thimbleful of sample and reagent volumes, repeated use of capillary, and the lowest test cost. By using DNA-FCB to qualify the target DNA, we can consumedly decrease the pollution of the environment.

In preparing DNA fluorescence capillary biosensor(DNA-FCB),capillary was used as carrier to immobilize DNA and complementary target DNA was sucked into the capillary for the hybridization to form spiral dual chain DNA in which berberine was embedded as the fluorescence labelling substance.By measuring the fluorescence intensity with a fluorospectrophotometer,the target DNA was detected qualitatively and quantitatively.Optimum conditions for the determination were found as follows: ① volume of sample solution taken: 12 μL;② range of linearity and linear regression equation: 2-10 μmol·L-1 of target DNA,y=9.52 x+9.22(r=0.991 2);③ detection limit: 1.16 μmol·L-1 of target DNA.The method of determination of target DNA with this biosensor was proved to be simple and convenient in operation,low in consumption of reagents and in cost for determination,as well as profitable to environmental protection.

The correlation of the fluorescence intensity of berberine hydrochloride(BB) with double-stranded DNA(dsDNA) was examined and the operation conditions for BB in agarose gels electrophoresis were optimized.The staining effect of BB was imaged and compared with that of ethidium bromide(EB).The results showed that the fluorescence intensity of BB was enhanced significantly by dsDNA and the increased intensity was proportional to the concentration of dsDNA.A nontoxic and simple staining method with fluorochrome BB for the detection of DNA in agarose gels was thus developed.The method can detect as little as 100 bp per band of DNA(10 ng) stained by 10 mg/L BB in gels.For small fragment of dsDNA,the sensitivity of BB was a bit lower than that of EB under the same experimental conditions,since BB was positively charged in alkaline solution leading to the decrease of DNA relative mobility.