| This thesis describes current approaches for the preparation of biodegradable polymers nanoparticles and their applications research in medical field. Experimental magnetic nanoparticles start fromĪ³-Fe2O3, with natural starch polymer coating. And two kinds of natural macromolecules biodegradable polymers, Poly-L-lysine(PLL) and Folic acid (FA-PEG-NH2), were used in this experiments to modify starch magnetic nanoparticles. Study its physical and chemical properties, and further biological medical application for magnetic hyperthermia.Modified magnetic starch nanoparticles (PLL-StNP@ Fe2O3&FA-StNP@ Fe2O3) were synthesized by conjugating PLL&FA-PEG-NH2 onto the surface of magnetic starch nanoparticles(StNP@ Fe2O3) prepared by reverse microemulsion method. The synthesized nanoparticles were investigated by transmission electron microscopy and zeta potential analysis. The average size of its well dispersed particles and the iron concentration detected by phenanthroline method were gained. Placing these nanoparticles in alternating magnetic field for 30 min could result in an increase in the suspension temperature from ambient temperature (37 oC) to a value between 42 and 43 oC. Co-cultured nanoparticles and Hela cell line or normal HUEC-12 cell line, and the biological effects at cellular level were investigated in alternating magnetic field using MTT assay, Hochest-PI double staining and flow cytometry analysis. Experimental results showed that functional nanoparticles within certain concentration range has no obvious effect on cell proliferation. When treated in magnetic field, apoptosis on Hela induced by these nanoparticles were obvious. Prussian blue staining analysis confirmed that the nanoparticles modified with PLL &FA had improved ability in tumor cell-targeting, compared with HUCE-12,and therefore, potential applications in biomedical and magnetocaloric areas. It is expected to be applied to tumor targeting therapy in the near future. |
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