| In this thesis,sodium selenium(Na2SeO3)and selenomethionine(SeMet)were used as model core materials,while chitosan was selected as wall material to prepare the selenium-loaded chitosan microencapsulation with emulsion cross-linking and monophasic coagulation methods,and these two forms of selenium were transformed into microcapsules in such a way eventually.Then,characters of the microencapsulation,such as its appearance,drug loading capacity,encapsulation efficiency and its sustained-release property in the simulated body fluid(SBF),were chose as the main criteria to value the quality of microencapsulation.Furthermore,the structure of the microencapsulation was characterized through atomic fluorescence spectroscopies,infrared analysis(IR),field emission scanning electron microscopy(FESEM),thermogravimetric analysis(Tg)and differential thermogravimetric analysis(DTg).Finally,on this basis,human breast cancer MCF-7 cells have been selected as a cell model to test the anticancer activity of microencapsulation in vitro.A new selenic complementary way for people who have been lacking selenium was expect to reach when the sustained-release property of the chitosan microencapsulation was combined with the vital physiological functions of selenium,at the same time,a certain of theoretical supports may be provided by this research for the anticancer study of selenium.Main results of this paper were described as follow:1.Sodium selenium and selenomethionine had been microencapsulated with chitosan by emulsion cross-linking method.The dosage of core material,the amount of cross-linking agent,the solidification temperature and the cross-linking time were selected as experimental variables during a single factor experiment,which was conducted to figure out how did these variables affect the preparation of selenium-loaded chitosan microencapsulation.Based on this single factor experiment,an orthogonal experiment was designed and conducted,and its results were analyzed by SPSS 20.0 to find out an optimal process conditions to produce microencapsulation.The results showed,under this optimal process condition,the appearance of microencapsulation was good,the encapsulation efficiency of Na2SeO3 and SeMet were 66.35%and 31.94%respectively,the drug loading capacity were 1.21%and 0.54%respectively.In addition to this,the sustained-release experiment in vitro revealed that,under the same condition,the accumulative releasing rate of SeMet-loaded and Na2SeO3-loaded chitosan microencapsulation were 40.12%and 15.28%,the former was higher than the latter.Furthermore,these two kinds of microencapsulation were soaked in SBF to release their core material for 0.5,3,10 and 50 hours,and then these different sustained-release solutions were obtained for conducting an anticancer experiment in vitro.Both two kinds of microencapsulation displayed anticancer activity in a degree.Their efficiency of proliferation inhibition on MCF-7 cell increased with the releasing time and reached the maximum after the sustained-release solution had been acting on the MCF-7 cells for 48 hours and the maximum of Na2SeO3-loaded and SeMet-loaded chitosan microencapsulation was 20.59%and 32.62%respectively.2.Selenomethionine had been microencapsulated in chitosan by monophasic coagulation method.The dosage of core material,the solidification temperature and time were selected as experimental variables during a single factor experiment,which was conducted to figure out how did these variables affect the preparation of selenium-loaded chitosan microencapsulation.Based on this single factor experiment,an orthogonal experiment was designed and conducted,and its results were analyzed by SPSS 20.0 to find out an optimal process conditions to produce microencapsulation.The results showed,under this optimal process condition,the appearance of microencapsulation was good,the encapsulation efficiency and the drug loading capacity were 5.11%and 0.22%respectively.In addition to this,the sustained-release experiment in vitro showed that the accumulative releasing rate of this microencapsulation was 95.31%and this was the highest accumulative releasing rate among the three kinds of microencapsulation.Furthermore,this microencapsulation was soaked in SBF to release its core material for 0.5,3,10 and 50 hours,and then these different sustained-release solutions were collected to conduct the anticancer experiment in vitro.It displayed anticancer activity in a degree The efficiency of proliferation inhibition on MCF-7 cell increased with the releasing time and reached the maximum after the sustained-release solution had been acting on the MCF-7 cell for 48 hours and the maximum was 62.32%. |
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