Sythesis Of Selenide Nano-Materials And The Application In Biology Sensor

Three kinds of selenide nanoparticals have been synthesized through hydrothermal route. The synthesized nanoparticles are well dispersed and have biology consistent ability as their surfaces are modified in the process of synthesis. The morphology and characteristic were characterized by TEM,SEM,XRD,EDS,XPS,UV-Vis,FT-IR respectively, and the possible growth mechanisms were elucidated based on our experimental results. The application of nanoparticles-based novel electrochemical DNA biosensor was studied and discussed.(1) Monodispersed silver selenide (Ag₂Se) nanoparticles have been prepared successfully by a hydrothermal reaction of Na2SeSO3 with [PVP(AgmIn)](n-m)- which is formed by AgNO3,KI and PVP. TEM revealed that the nanoparticles are much like husked rice with length of about 60～80 nm and width of about 30～40nm. [PVP(AgmIn)](n-m)- acted an important role in the reaction. The formation rate of Ag₂Se crystal cores and the growth direction could be well controlled as the protection effect of PVP. Husked rice-like Ag₂Se nanoparticles with uniform size were obtained in the condition of high concentration of PVP. The XPS and FT-IR test indicted that there was a great number of PVP modified on the surface of Ag₂Se nanoparticles. The modification effect was not only a physical adsorption but also a chemical coordination. Ag₂Se was bound to the probe DNA via the formation of the hydrogen bond between–C=O of PVP in the modified Ag₂Se and–NH2 in the probe DNA. The proposed method showed a good and distinguishable ability to the three-base mismatch or non-complementary sequences with the complementary sequences. DNA specific-sequence related to PEP promoter gene in the transgenic plants was determined with a detection range from 1.0×10^-12 to 1.0×10^-8 mol L^-1 and a detection limit of 2.3×10^-13 mol L^-1(3σ).(2) Lead selenide (PbSe) nanoparticles were synthesized by the reaction between Pb(CH3COO)2 and NaHSe under hydrothermal conditions in the presence of CTAB at 150℃for 24h. The X-ray diffraction (XRD) pattern indicated that the product was cubic PbSe. Transmission electron microscopy (TEM) revealed that the nanoparticales are about 40 nm in diameter. The FT-IR test indicted the adsorption of CTAB on the surface of PbSe nanoparticles. The ionization of CTAB produced cation CTA+ on the surface of PbSe nanoparticles and made the nanoparticles with positive charge. As the -COO- of DNA made the DNA with negative charge, the PbSe nanoparticles can adsorbed the negative charged oligonucleotides by electrostatic interaction to form a nanoparticle labeled oligonucleotides probe. The PbSe nanoparticles showed a good distinguishable ability to the two-base mismatch or non-complementary sequences with the complementary sequences. DNA specific-sequence related to CaMV35S promoter gene in the transgenic plants was determined with a detection range from 5.0×10^-12 to 5.0×10^-7 mol/L and a detection limit of 6.1×10^-13 mol/L (3σ).(3) A simple biomolecule-assisted hydrothermal approach was developed to synthesize zinc selenide (ZnSe) nanoparticles. The X-ray diffraction (XRD) pattern indicated that the as-prepared product was cubic ZnSe. The TEM images showed the size of the ZnSe nanosphere was 100nm in diameter. The L-glutamic acid acted as complexing agent and biomolecule templet to combine with Zn2+ in the process of the reaction. The FT-IR studies of the as-prepared ZnSe provide preliminary proof for confirming the adsorption between ZnSe nanoparticles and glutamic acid. Glutamic acid was the bridging agent between DNA molecule and zinc selenide nanospheres. So the ZnSe nanoshperes could be used for the detection of the DNA hybridization. DNA specific-sequence related to PAT gene in the transgenic plants was determined with a detection range from 1.0×10-11 to 1.0×10^-7 mol L^-1 and a detection limit of 4.7×10^-12 mol L^-1 (3σ).