Study Of Immunosensors Based On Magnetic Nanowires

The research of magnetic nanowires is hot spot in nanomaterial fields, because of both the normal characteristic of nanomaterial and the unique excellent magnetic properties. At present, many researches are the preparation and characterization of nanowires. However, the deep research of nanowires in immunosensors application is less reported.In this paper, a new immunoassay, magnetic nanowires as biological carrier, is given out. Magnetic nanowires are use in immunosensors first time. And new attempts for immobilization technology of biological active material and application of magnetic nanowires are tried. These widen thought of immunosensors' optimization and development. Based on magnetic nanowires/chitosan/α-HCG, the test strips of immunochromatography were prepared and tested. Mini immunosensor detection system based on magnetic nanowires was developed. Magnetic nanowires solution with different concentration was detected by it. This provides a new way in integration and miniaturization of immunosensors, as well as on-line analysis and rapid detection of biological sample.Pour anodic aluminum oxide (AAO) template was prepared by two-step oxide method and characterized. Forming mechanism was researched and experiment condition was optimized. The nano-holes equably distribute and parallel each other in AAO template. They are equilateral hexagon with 50 ran diameter, 10~6/ mm~2 density and 10 urn length.Based on AAO template after modified with step-reduce-voltage method, Fe and Ni nanowire arrays were prepared by AC electrochemical deposition method and characterized. Their diameter is 50 nm. And their length is 750 nm. Magnetism of nanowires was analyzed and the result shown that the magnetization direction was obvious uniaxial magnetic anisotropy because of figure anisotropy of nanowires.Fe nanowires were coated by chitosan. Magnetic nanowires/chitosan was prepared by glutaraldehyde as cross-linking reagent. Forming mechanism was researched. Adsorbing bovine serum albumin (BAS) capacity was tested with different pH buffer solution and different concentration BAS. The result shown that when the concentration of BSA is 2.0 mg/mL and pH of buffer solution is 5.0, the maximum of adsorption is 148.4 mg/g. The biological probes of magnetic nanowires/chitosan/α-HCG were prepared by cross-linking withα-HCG. The immunochromatographic test strips of were prepared by magnetic nanowires/chitosan/α-HCG,β-HCG and IgG. And different concentration HCG antigen was tested. The result shown that sensitivity of test strips was 10 mlU/mL. Compared with 25 mlU/mL sensitivity of colloidal gold test strips in market, the detection time of pregnancy can be forward 2～3 days.An easy operating, easy taking and rapid reacting magnetic immunosensor detection system was developed. After optimized the geometry parameter of detect coil, different concentration sample were detecting. The result shown that the sensitivity of system was 0.2 mg/mL.