| As one of the drug controlled release methods, intelligent responsive nano-drugs have attracted widespread attention. It is important for controlling the drug release rapid rate and reducing the side effects of drugs. According to the small pH change in different tissues of human body (pH value of normal tissue cells is closed to neutral. But the value of diseased tissue cells is from 5.5 to 6.9), pH-responsive intelligent drugs have become a hot spot. In this paper, a pH-sensitive magnetic naocarrier with good dispersion and low cytotoxicity had been prepared. The drug loading property was also been studied. The main contents were as follows:1. Poly (amido amine) dendrimer (PAMAM, From 0.5 generation to 2.5 generation, 0.5G-2.5G) was synthesized by divergent method. The yield and purity revealed that the best synthesis condition was:25℃,24h, molPAMAM:moIEDA/MA=1:24.2. Fe3O4 nanoparticles were synthesized by hydrothermal method and chemical coprecipitation method. Afterwards, several substances were used to prepare the hydrophilic magnetic nanoparticles contain amino groups (Fe3O4-NH2). The results showed that the nanoparticles modified with APTES were spherical with the size of 17nm. These nanoparticles had good dispersion and magnetic response.3. Fe3O4-NH2 nanoparticles were modified with 2.5G PAMAM by several steps or by one step. Then Hydrazine hydrate was added to react with terminal ester groups of PAMAM to form the hydrazide groups (-NH-NH2). The results showed that PAMAM was grafted to Fe3O4-NH2 successfully and PAMAM didn’t change the basal crystalline phase of Fe3O4 PAMAM could be grafted to Fe3O4-NH2 better by one step reaction. The resulted nanocarrie (Fe3O4-PAMAM-H) had low cytotoxicity.4. Doxorubicin (DOX) was loaded to the nanocarrier by hydrazine bond, which hydrolyzes in the acidic environment. The results showed that the drug loading and entrapment efficiency of Fe3O4-PAMAM-H synthesized by one step were found to be higher, and the drug release was pH-sensitive. |
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