Biodegradable Preparation And Mechanism Of The Magnetic Nanoparticles

Biocompatible and biodegradable magnetic nanospheres are synthesized by coating magnetic materials with biocompatible and biodegradable materials. They not only have surface functionality and high magnetic responsiveness as the polymer nanospheres, but also have shells made from natural and green materials, so their potential applications are much greater than normal polymer nanospheres, especially in medicine field. Magnetic nanospheres synthesized in this paper are based on magnetic targeted nanoparticle drug delivery system. Two kinds of biocompatible and biodegradable magnetic nanospheres were synthesized by two different novel methods in this paper. Their optimal synthesis conditions were got and their formation mechanisms were expounded. The details are described as below:(1)Fe3O4 modified by OA and UA as the cores, bovine serum albumin (BSA) as the shells and cyclohexane as the agency, Fe3O4/BSA magnetic nanospheres were synthesized by sonochemical method. The effects of various factors in the experiments were studied, including BSA dosage, ferrofluid's concentration and dosage, ultrasonic time, ultrasonic power, pre-emulsification and water cooling. At last, optimal conditions were got. Coating effect and structure of the nanospheres synthesized under the optimal conditions were tested and characterized by FT-IR, TEM, SEM, TG and VSM. The results show that the nanospheres have clear core-shell structure, small size (approximately 100 nm), good sphericity and dispersibility, abundant functional groups, large saturated magnetization (38.5 emu/g) and superparamagnetism, high Fe3O4 content (57.6%).The formation mechanism of Fe3O4/BSA magnetic nanospheres synthesized by sonochemical method was analysed and expounded in detail, and it was proved through contrast experiments.(2) Low-temperature hydrothermal method was modified by us. With this method, carbonaceous polysaccharide microspheres and carbonaceous polysaccharide coated Fe3O4 (Fe3O4@CP) magnetic nanospheres were synthesized. It was discovered that the yield and coating effect will be improved with the help of little NaOH. The optimal conditions were also found through a lot of experiments. Various properties of the Fe3O4@CP magnetic nanospheres synthesized under the optimal conditions were tested and characterized. They showed high saturated magnetization (60.629 emu/g) in the VSM test, high Fe3O4 content (81.7%) in the TG test. The TEM images show that their particle size is less than 300 nm. It was demonstrated that Fe3O4@CP magnetic nanospheres can not be synthesized with hydrothermal method but unformed agglomerates when small size Fe3O4 particles (less than 20 nm) were used as the cores, and the reasons were analysed. The formation mechanisms of carbonaceous polysaccharide microspheres and Fe3O4@CP magnetic nanospheres were inferred, and unique viewpoints were put forward in the paper.