| Scientists pay a lot of attention on the multi-porous structure polymer, due to its low density, high specific surface area, transmission capacity, surface properties and internal diffusion resistance, and its potential application value on ion exchange, solid phase extraction and chromatography, biological macromolecular carrier and tissue regeneration scaffold field. Biodegradable chitosan (CS) is a natural polymer materials widely distributed in the nature, which can widely used in medicine, environmental protection, food and so on, for its good biocompatibility characteristic. Based on the above, this research prepared multi-porous polymer/chitosan composite microspheres combined with porous polymer and chitosan, and its advantages. The main content of this research is:(1) Swelled the sulfonated polystyrene (SPS) into a multi-porous structure by using the nonsolvent/solvent induced phase separation method, and the research on the influence of different conditions on the multi-porous microspheres. (2) The preparation of multi-porous SPS/CS microspheres by loaded chitosan on multi-porous surface of sulfonated polystyrene microspheres, and the study its sustained release performance and release kinetics. (3) The preparation of the multi-porous SPS/CS/Fe3O4 magnetic microspheres using the situ load of Fe3O4 nanoparticles on the surface of multi-porous SPS/CS, and the research about drugs slow-release performance and the release kinetics of magnetic porous microspheres. The specific content briefly as follows:1. Swelled the sulfonated polystyrene (SPS) into a multi-porous structure by using the nonsolvent/solvent induced phase separation method. Using sulfonated polystyrene (SPS) as template microspheres, because sulfonated SPS microspheres has certain hydrophilicity. So the SPS tend to gather in oil-water interface (butyl alcohol/water interface), when SPS microspheres were added into the oil phase and water phase (butanol/n-heptane) mixture. In the process of heating reaction, SPS was swelling outside-in gradually by the oil phase nonsolvent (n-heptane). At the same time, butyl alcohol and water spread into the microspheres, As a result of the strong hydrophilicity-SO3H groups on SPS chain segment, the water molecule seeped and gathered into the SPS, forming a partial phase separation phenomenon inside the SPS. Finally, the porous structure was formed after dried. At the same time, the morphology influence of the porous microspheres SPS on the condition of the different proportion of solvent, tetrahydrofuran and n-heptane, alcohol water ratio and reaction time was discussed.2. Dispersed chitosan in acetic acid and water mixture, and added in porous SPS, because the electrostatic attraction of the sulfonic acid group on the SPS and the amino groups on chitosan, chitosan loaded onto the porous microspheres SPS, then added a small amount of crosslinking agent glutaraldehyde. Finally, the SPS/CS microspheres were obtained after Centrifugal cleaning. By changing the system temperature and glutaraldehyde crosslinking time of chitosan, studied the change condition the morphology influence of porous SPS/CS microspheres. Finally using porous composite SPS/CS as drug carrier, sodium salicylate as model drug, studied sustained release performance and release dynamics research of the porous SPS/CS microspheres under different pH conditions proved that the porous SPS/CS microspheres with good pH responsive and its release kinetics conform to pseudo-first-order kinetic model.3. Using porous SPS/CS as reactor, the Fe3+, Fe2+ ion adsorbed on CS porous microspheres surface, Fe3O4 nanoparticles situ generated on the surface porous SPS/CS microspheres, adjusting the pH value of solution to alkaline, obtained porous SPS/CS/Fe3O4 magnetic microspheres and study the influence of different adsorption time on the morphology of magnetic porous microspheres and grain size and content of Fe3O4 nanoparticles. At the same time, studied the two-step method of the Fe3O4 nanoparticles nucleation and grow to prepare porous SPS/CS/Fe3O4 magnetic microspheres, and compared the grain size, content and external magnetic responsiveness of Fe3O4 nanoparticles prepared by one-step method and two-step method. Finally, studied sustained release properties and release kinetics of the porous SPS/CS/Fe3O4 magnetic microspheres with sodium salicylate as model drug. |
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