The Applications Of Magnetic Silica Micropheres In Biomedicine

Multifunctional magnetic silica microphere are a novel nanoparticals material，in which the silica is coated on the superparamagnetic core and is modified withcarboxyl,hydroxyl and amion groups. Fe₃O₄magnetic nanoparticles are particularuseful in imaging and separation techniques due to their basic magnetic property.AndMultifunctional magnetic silical microphere can connect with proteins, DNA,antibody and graphere oxide via covalent and noncovalent. According to theseadvantags, we focus on the application of multifunctional magnetic silical micropherein the biomedical analysis in this paper.In the chapter1, we described the attractive properities and synthesis of magneticsilica microphere.Then we focused on their applications in bioanalysis andbiomedicine.In the chapter2, based on the advantages of RLS technique and the specificity ofimmunoreaction, we developed a novel method for the detection of AIV antigenbased on resonance light scattering technique in this study. Firstly, we preparedamine-functionalized magnetic silica nanoparticles （MNs）. Then, MNs/AIV antibodywas formed via covalent binding between amino groups and amino groups on thesurface of MNs and protein by glutaraldehyde. When AIV antigen was added to thesystem, the immunocomplex of MNs/AIV antibody-AIV antigen were formed due tothe high specificity of the immunoreaction of antibody-antigen. This method wasapplied to the analysis of AIV antigen in spiked chicken serum samples and salivasamples with satisfactory results.In the chapter3, a graphene oxide （GO）-based multifunctional hybrid has beendeveloped for loading and delivery of anticancer drugs. First, we preparedamine-functionalized magnetic/fluorescent silica nanoparticles, then, the fluorescentmagnetic SiO₂microspheres were covalently grafted onto GO via a facile amidationprocess between the carboxyl groups on GO and the amino groups on SiO₂microspheres. Doxorubicine （DOX） was chosen as a representative of aromatic anti-cancer, which can easily adsorb onto GO via π-πstacking and hydrophobicreaction. The GO-based fluorescent magnetic hybirds were obtained, and used asnovel carriers for loading and delivery of drug in HepG2cell.The cell apoptosis wasobserved after cell phagocytosed the DOX loaded magnetic fluorescent hybrids.