Preparation And Characterization Fluorescent Magnetic Target Drug Delivery System

The magnetic target drug delivery system has various applications in the field of cancer treatment. And its value depends on whether the system possesses superparamagnetic, biocompatibility, effectiveness of drugs and otherwise. In recent years, the preparation of multi-functional magnetic target drug delivery system has become a new hotspot of cancer treatment to achieve its excellent magnetic response, drug activity and targeted tracing, etc. In the context, three procedures are generally carried out in the experiments. The synthesis of superparamagnetic nano-magnetic core, magnetic microspheres(The first part:Chapter2, Chapter3), fluorescent magnetic microspheres, magnetic drug microspheres(The second part: Chapter4, Chapter5), and fluorescent magnetic anticancer microspheres(The third part: Chapter6) were studied thoroughly. And then the structures, performance, and formation mechanism of the system were totally characterized and researched. The main results are included as follows.(1) The first:Two kinds of iron oxide (Fe3O4) nanoparticles were synthesized by hydrothermal co-precipitation method and thermal decomposition method. And NPs’properties such as magnetic property, thermal-analysis, and particle morphology, etc., were analyzed and compared for better one. Finally, the hydrothermal co-precipitation method was chosen as the preparation method of magnetic nanoparticles in the following experiments.The magnetic albumin microspheres were using through an ultrasonic emulsion polymerization route. The repetitious experiments were using to discuss the impacts of different reaction conditions and then get the optimized one. There were also discussions about the principle of ultrasonic emulsion polymerization reaction.(2) The second:The fluorescent magnetic microspheres were prepared via ultrasonic emulsion polymerization method. There were two routes to introduce the fluorescence into microspheres. One was modifying bovine serum albumin with fluorescence before ultrasonic polymerization. The other way was modifying the shells after microspheres being prepared. The experimental results showed that the fluorescent modification before ultrasonic polymerization may affect the ability of BSA to form a disulfide bond between the protein molecules, so as to affect the formation of protein shell. While the fluorescent modification after ultrasonic polymerization would avoid this problem. According to the characterization, the magnetic responsiveness and structural stability of fluorescent magnetic microspheres were not affected by fluorescent modification. By control experiments about fluorescent spectrum, the fluorescent intensity decreased with the reduction of the sample concentration.Magnetic tetracycline microspheres were prepared by combining ultrasonic emulsion polymerization with ultrafine grinding technology. Superfine technology took average particle size of tetracycline powder down to about1μm so as to make the drug powder easier to dissolve in magnetic fluid solution, which was useful for the distribution of tetracycline drug particles in the emulsion reaction system. The preparation of magnetic tetracycline microspheres would be better to enable them dispersed better in the microemulsion droplets. Based on the characterization results of transmission electron microscopy (TEM), vibration sample magnetometer, bacterial inhibition experiments and other tests, it could be found that the structure of microspheres were not break down when the drug was coated. In the antibacterial experiments, the magnetic tetracycline microspheres had obvious drug activity compared to the control groups. It showed that magnetic microspheres prepared by ultrasonic emulsion polymerization could be used to load therapeutic drugs and be transmitted to the target.(3) The third:The fluorescent magnetic anticancer microspheres were prepared according to the experience above. To expand applications of ultrasonic emulsion polymerization method, hydrophilic fluorouracil was chosen as the coated drug. Hydrophobic fluorouracil microparticles were made by using a wet ball mil land and adding the stearic acid as a modifier, which can easily dispersed in magnetic fluid. Rhodamine B isothiocyanate was modified onto the surface of microspheres after loading the drug and successfully obtained fluorescent magnetic anticancer microspheres. Through vibrating sample magnetometer (VSM) and fluorescence analysis, fluorescent magnetic anticancer microspheres had good superparamagnetic and fluorescent light-emitting properties. In addition, MTT test showed that fluorescent magnetic anticancer microspheres had a toxic effect on cancer cells.In summary, this paper focus on the preparation of magnetic target drug delivery system, such as iron oxide nano-magnetic core, magnetic albumin microspheres, fluorescent magnetic microspheres, magnetic tetracycline microspheres and fluorescent magnetic anticancer microspheres by using ultrasonic emulsion polymerization method and ultrafine grinding technology. A series of problems about preparation of magnetic target drug delivery system have been discussed and resolved in the paper. The magnetic target drug delivery system possesses high saturation magnetization (above35emu/g), small microsphere diameter(less than300nm), fluorescent group, and medical activity. These expanded the application of magnetic target drug delivery system in the field of medicine.