| Nowadays, more and more people realize the importance of health. However, human beings cannot avoid the attack of cancer because of the environment and the living habits of themselves.Fortunately, the appearance of the drug carriers for the treatment of cancer, for example the polymer hydrogels, has brought about new hope and attracted extensive attention. It is one of the research focuses in recent years for us how to guarantee the harmlessness of the drug carriers to the human body, good biocompatibility and nontoxic side effects. In this thesis, we synthesized two kinds of biomedical polymer materials. The specific studies were summarized as follows:1. A series of pH sensitive poly(N-isopropylacrylamide)-co-carboxymethyl chitosan-carbon nanotubes/carboxylic carbon nanotubes (PNIPAM/CMCS/CNTs (CNT-COOH)) semi-interpenetrating nanohybrid hydrogels were designed and developed by free radical crosslinking polymerization of NIP AM monomer in the presence of CMCS and CNTs (CNT-COOH). The structure and morphology of nanohybrid hydrogels were characterized by FTIR, DSC, and ESEM etc. The results showed that the PNIPAM/CMCS/CNTs (CNT-COOH) hydrogels were successfully synthesized. The swelling properties of the hydrogels and the change in the swelling with temperature and pH were investigated, and the dynamic analysis was made for these hydrogels. The swelling properties of both the hydrogels increased with the time and finally achieved a balance. The swelling curves and the maximum swelling ratios of the prepared hydrogels with CNTs-COOH were obviously higher than those with CNTs, which is ascribed to the introduction of the carboxylic acid groups that enhanced the hydrophilicity of the hydrogels. Both the two hydrogels showed obvious temperature and pH sensitivity. The swelling properties of the hydrogels with CNTs-COOH in different pH solutions were much better than those with CNTs. With increasing the temperature, the swelling properties of both the hydrogels changed regularly and the phase transition happened at 32℃ with no obvious differences.2. The loading of doxorubicin hydrochloride (DOX) in the nanohybrid hydrogels and selective release from a series of the DOX-loaded nanohybrid hydrogels which were synthesized with CNTs-COOH were studied at two different temperature conditions of 37 and 38℃ and the dynamic analysis was also conducted. The results showed that in the case of PNIPAM/CMCS/CNTs-COOH hydrogels, the release amount of the drug from the hydrogels was increased with increasing the CNTs-COOH content from 1 to 5%. The maximal loading amount of the drug was low at about 42%, whereas the amount release of the drug was high. Thus the polymer hydrogels were demonstrated to have the characteristic of slow release and specific medication.3. Hydrophobic ferroferric oxide-b-poly(N-isopropylacrylamide)-b-polystyrene (Fe3O4@PNIPAM-b-PS) block copolymer microspheres were designed and developed through atom transfer radical polymerization and the influences of silane coupling agents on main performances of the microspheres was studied. The structure and morphologies of the microspheres were confirmed by FTIR, XRD, DLS, ESEM, and TEM etc. XRD findings showed that the Fe3O4 crystal forms were not changed during the reaction. The diameters of the polymer magnetic microspheres at different temperatures were measured by DLS, and the results showed that the designed microspheres were temperature sensitive. Furthermore, we achieved the expected results by testing the contact angle of the microspheres, which was about 105.1°.Further application studies would be done in the subsequent work. |
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