Synthesis And Properties Of Magnetic Polyamide-amine Dendrimer

The magnetic materials are ’widely used in magnetic,mechanical,optical,electronic,chemical,medical,and biological fields,because of its special properties,such as super paramagnetic,large specific surface area,and so on.Dendrimers are a new kind of polymer materials with special three-dimensional space structure.Compared with the common polymers,dendrimers can precisely control the molecular structure and molecular weight via stepwise synthesis.There are a large number of cavities inside of the molecules,and a lot of functional groups at the end of the molecules.Because of this unique molecular structure,dendrimers have had a wide use in nanotechnology,biology,medicine,photoelectricity,catalysis field and so on.Based on such a background,in this paper we used Fe3O4 nanoparticles as a core to further synthesize a series of magnetic polyamidoamine dendrimers,Mag-PAMAM-Gn and some related end-modified products,Mag-PAMAM-Gn-COOH;then the complex formed from Mag-PAMAM-G2-COOH and nickel ion was used to quickly separate the His-tag protein.Details are as follows:1.The Fe304 nanoparticles were synthesized using FeCl3·6H2O and FeCl2·4H2O via co-precipitation method.The samples were characterized with IR,TG and TEM.2.A series of Mag-PAMAM dendrimers with Fe3O4 nanoparticles as the core were synthesized via divergent growth pathway.The products were confirmed by IR,TG and TEM.3.Tert-butyl acrylate was used to modify the terminal groups of Mag-PAMAM via Michael addition reaction.Then Boc group was removed by using trifluoroacetic acid(TFA)to obtain the Mag-PAMAM dendrimers with carboxyl groups as terminal groups.The samples were also characterized with IR,TG and TEM.4.The complex Mag-PAMAM-G2-COOH-Ni was obtained by Mag-PAMAM-G2-COOH and NiSO4·6H2O,and ICP-MS was employed for the detection of iron,nickel content.5.In order to compare the proteins adsorption ability of the targeted product,His-GFP adsorption experiments and protein electrophoresis tests were subsequently carried out with the target product Mag-PAMAM-G2-COOH-Ni and the commercial Ni-charged MagBeads.