| Nano-based drug delivery system is one of the most attracting methods for the treatment of cancer which is developed by nano biomedical engineering. In general, drug carrier materials used in the drug delivery system should contain special characteristics such as non-toxic, biodegradable, biocompatibility, and absorbability among which poly(lactic acid)(PLA), poly(lactic-co-glycolic acid)(PLGA), poly(?-caprolactone)(PCL), chitosan, dextran, protein, starch, cellulose and their derivatives were widely applied.Many preparation approaches were reported to generate dextran microgels. However, they are not suitable to be used as drug carrier due to their complex synthetic process, high cost and inhomogenous particle size which is disadvantage for the drug uptake and release. In order to overcome these problems, dextranand protein with good biocompatibility and easy functionality were utilized for the preparation of novel drug delivery carriers, and the following work were carried out:(1) The preparation method of a dextran-based multifunctional nano-drug carrier system and its drug release properties;(2) Transferrin as a protectant for the production of gold nanoclusters, and the protein as a drug carrier to load anticancer drug-methotrexate(MTX).(1) In this work, we present a facile and effective synthetic route for the preparation of functional dextran hydrogels, which can effectively encapsulate hydrophobic dye-Nile Red, hydrophobic drug-paclitaxel(PTX), B-raf inhibitors, and/or hydrophobic and functional nanoparticles-Fe3O4 nanoparticles, Cd Se-Zn S quantum dots and Cu Zn Ln S quantum dots(QDs).By modifying the natural polysaccharides using cholesterol as the hydrophobic group, we produced a new kind of amphiphilic polysaccharide derivative. The hydrophobic drug(for example paclitaxel), QDs, or Fe3O4 NPs are mixed with the DMSO solution of polysaccharide derivatives. Then a lot of water was added to the mixture to induce the aggreagation of dextran microgels. Multifunctional dextran microgels were generated through simply stirring or sonication.Fourier transforminfrared spectroscopy(FTIR) was applied for the chemical structure characterization of the amphiphilic polysaccharide derivatives.The morphology, size distribution of the multifunctional dextran microgels were studied by the dynamic light scattering(DLS), and transmission electron microscope(TEM). The dextran microgels encapsulating quantum dots and fluorescent dyes were measured by fluorescence spectrophotometer. The drug loading ratio of the dextran microgels encapsulating paclitaxel and B-raf inhibitors were tested with ultraviolet-visible spectrophotometer(UV-vis). The magnetic response properties of the dextran microgels encapsulating Fe3O4 magnetic nanoparticles were investigated by permanent magnet. The dextran microgels encapsulating paclitaxel as example to carry out the drug release behavior in vitro. The results confirmed that the functional dextran microgels have potential application in the area of drug delivery and release.(2) Transferrin(Tf) was used as a protectant for synthesis of gold nanoclusters. Because of it's effective chelating and functional groups such as amino, thiol or carboxyl groups, protein can be used as drug carrier encapsulating antitumor drug methotrexate(MTX).Herein, transferrin was selected as the model protein for the synthesis of Au NCs. Transferrin reacted with HAu Cl4 at the physiological temperature. The amino group of protein reacted with the carboxyl of methotrexate for the generation of MTX-Tf-Au NCs. The reaction products were investigated by UV-vis, fluorescence spectrophotometer, transmission electron microscopy. The drug loading ratios of drug methotrexate were characterized by UV-vis. The results confirmed that fluorescence intensity and the resulting loading efficiency of our preparation are high. |
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