Application Of Magnetic Iron Oxide Nanomaterials In Tumor Imaging And Biomimetic Magnetic Separation

The oil phase iron oxide nanoparticles were prepared by high temperature decomposition method,and they were transferred to the aqueous phase by ligand exchange method,and a further modified maleimide group was introduced on the surface of the nanoparticles.A tumor microenvironment responsive nanoprobe was developed for enhanced tumor imaging through in situ crosslinking of the Fe3O4 nanoparticles modified with a responsive peptide sequence in which a tumor-specific Arg-Gly-Asp peptide for tumor targeting and a self-peptide as a “mark of self” was linked through a disulfide bond.Positioning the self-peptide at the outmost layer was aimed at delaying the clearance of the nanoparticles from the bloodstream.Then,the probe was labeled with radionuclide,and MRI/SPECT dual modality imaging probe was prepared and used for tumour imaging in vivo.Both in vitro and in vivo experiments demonstrated that the aggregation substantially improved the magnetic resonance imaging?MRI?contrast enhancement performance of Fe3O4 particles.By labelling the responsive particle probe with 99 m Tc,single-photon emission computed tomography?SPECT?was enabled not only for verifying the enhanced imaging capacity of the crosslinked Fe3O4 particles,but also for achieving sensitive dual modality imaging of tumors in vivo.The no velty of the current probe lies in the combination of tumor microenvironment triggered aggregation of Fe3O4 nanoparticles for boosting the T2 MRI effect,with anti-phagocytosis surface coating,active targeting,and dual-modality imaging.Then,designed the Ca²⁺ triggered Fe₃O₄ nanoparticles aggregation was prepared.The immunized magnetic beads were prepared on the surface coated with Salmonella sp,and the capture experiments were carried out on Salmonella sp,and the better capture efficiency was obtained.