Magnetic Nanoparticles: Computer Simulations, Chemical Syntheses, and Biomedical Diagnosises

摘要

In this chapter, we review some our recent works on magnetic nanoparrticles: computer simulations, chemical syntheses, and biomedical diagnoses. (ⅰ) First, basing on Monte Carlo simulation, we will show the influence of concentration as well as size distribution on magnetic properties of samples, namely blocking temperature and coercive field. The simulated results are clearly explained and compared with recent experiments. (ⅱ) In synthesis section, magnetite (Fe_3O_4) nanoparticles are prepared by the chemical procedure. The surface of nanoparticles is covered the SiO_2 layer via the sol-gel method. The x-ray diffraction (XRD) spectra, vibrating sample magnetometer (VSM) spectra, infrared absorption (IR) spectra, Field Emission Scanning Microscope (FESEM) images, and Transmission Electron Microscope (TEM) images are used to obtain characters of sample. (ⅲ) Finally, we perform the immobilization of antibodies on magnetic nanoparticles to apply in the biomedical diagnosis, namely anti-HPV18 antibody for cervical cancer diagnosis and E.Coli O157:H7 for diarrhea diagnosis. Thermal analyses (TA/TDA) are carried out to check the immobilization of anti-HPV18 antibody on the surface of Fe_3O_4/SiO_2 nanoparticles. ELISA test are employed to detect E.Coli O157:H7 based on the Fe_3O_4 magnetic nanoparticles with SiO_2 coating layer attached to E.Coli O157:H7 antibodies, and compared with normal analysis methods.