硒纳米颗粒的生物制备及优化

发布时间：2018-05-16 01:48

本文选题：胎牛血清 + 壳聚糖　；参考：《山东大学》2016年硕士论文

【摘要】：硒是人体生理活动过程中非常重要的微量元素,体内缺硒以及摄入过量的硒均会导致相应的病症。世界上有很多地区缺硒,我国也属于非常缺乏硒元素的地区之一,研究和发展补硒类型的保健食物刻不容缓。硒纳米颗粒(SeNPs)属于纳米级的单质硒,其不仅具有补硒效应,还具有较高的生物活性以及较低的生物毒性,食用安全性得到比较有效的改良,因此在食品领域得到比较广泛的应用。本文选用解淀粉芽孢杆菌为实验菌种,利用其对高价态硒(亚硒酸钠)的还原作用,将SeO32-还原成单质Se0,制备胶体状硒纳米颗粒。本文探究了胞外聚合物(EPS)在合成硒纳米颗粒过程中所起的作用,EPS是含有蛋白质成分的复杂有机层,它在硒纳米颗粒的还原过程中起重要作用,且硒纳米颗粒被EPS包裹有助于它的长期稳定。本论文探讨了反应时间、温度、pH、菌液初始浓度、摇床转速、装液量等对硒纳米颗粒转化率的影响,并寻找最佳反应条件。然而当前生物法制备硒纳米颗粒转化率较低、稳定性较差,因此我们试图寻找一种方法来提高解淀粉芽孢杆菌EPS中蛋白质及其他官能团的性质,进而提高硒纳米颗粒的转化率。本研究中分别使用胎牛血清(FBS)和壳聚糖(chitosan)作为添加剂,用来促进细胞生长,提高生物酶活性,进而达到加快反应速度,提高硒纳米颗粒转化率,提高颗粒分散稳定性,优化制备的硒纳米颗粒性状的目的。本论文还探究了添加剂胎牛血清或者壳聚糖对解淀粉芽孢杆菌EPS组分及结构的影响。FT-IR光谱和XPS光谱证明添加胎牛血清或者壳聚糖后,EPS中蛋白质和碳水化合物及其它官能团都有一定程度的增加,部分官能团的结构也产生一定的变化,这将促进细胞活性,进而提高氧化还原反应的速度以及硒纳米颗粒的转化效率。XRD和EDX分析表明,胎牛血清或者壳聚糖的添加,使硒纳米颗粒不仅在数量上有一定程度的增加,还具有更高的结晶度,以及更稳定的性质,这表明胎牛血清或者壳聚糖的添加可以优化硒纳米颗粒的性状。此外,ζ-电位分析表明,添加了胎牛血清或者壳聚糖之后,生成的硒纳米颗粒具有更高的ζ-电位和等电点,使硒纳米颗粒具有更高的分散稳定性,有利于硒纳米颗粒的长期储存。
[Abstract]:Selenium is a very important trace element in the physiological process of human body. There are many regions in the world that lack selenium, and our country is also one of the regions with very lack of selenium, so it is urgent to study and develop the type of health food supplemented with selenium. Selenium nanoparticles (SeNPs) is a kind of selenium, which not only has the effect of selenium supplementation, but also has higher biological activity and lower biotoxicity, so the edible safety is improved effectively. Therefore, it is widely used in the field of food. In this paper, Bacillus amylolyticus was selected as the experimental strain, and the colloidal selenium nanoparticles were prepared by reducing the high valence selenium (sodium selenite) to single substance Se0. In this paper, the role of extracellular polymer EPS in the synthesis of selenium nanoparticles is investigated. EPS is a complex organic layer containing protein, which plays an important role in the reduction of selenium nanoparticles. And the EPS encapsulation of selenium nanoparticles contributes to its long-term stability. In this paper, the effects of reaction time, temperature and pH, the initial concentration of bacteria solution, the rotating speed of shaking bed and the amount of liquid filled on the conversion rate of selenium nanoparticles were discussed, and the optimum reaction conditions were found. However, the conversion rate of selenium nanoparticles prepared by biological method is low and the stability is poor. So we try to find a way to improve the properties of protein and other functional groups in Bacillus amylolyticus EPS, and then improve the conversion rate of selenium nanoparticles. In this study, fetal bovine serum FBSand chitosan were used as additives to promote cell growth, increase enzyme activity, accelerate the reaction rate, improve the conversion of selenium nanoparticles, and improve the dispersion stability of selenium nanoparticles. Objective to optimize the properties of selenium nanoparticles. The effects of additive fetal bovine serum or chitosan on the composition and structure of EPS of Bacillus amylolyticus were also investigated. FT-IR and XPS spectra showed that the protein and carbohydrate in EPS were determined by adding fetal bovine serum or chitosan. Its functional groups have increased to a certain extent, The structure of some functional groups also changed to some extent, which would promote cell activity, and then increase the reaction rate of redox reaction and the conversion efficiency of selenium nanoparticles. XRD and EDX analysis showed that the addition of fetal bovine serum or chitosan, The selenium nanoparticles not only increased in quantity, but also had higher crystallinity and more stable properties, which indicated that the addition of fetal bovine serum or chitosan could optimize the properties of selenium nanoparticles. In addition, 味 -potential analysis showed that after adding fetal bovine serum or chitosan, the resulting selenium nanoparticles had higher Zeta potential and isoelectric point, which resulted in higher dispersion stability of selenium nanoparticles, which was beneficial to the long-term storage of selenium nanoparticles.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O613.52;TB383.1

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