【作者】 董晶莹；

【导师】 刘宁；

【作者基本信息】 东北农业大学 ， 食品科学， 2005， 硕士

【摘要】 纳米材料又称为超微颗粒材料,是由纳米粒子组成,既非微观系统亦非宏观系统,而是一种典型的介观系统。纳米颗粒具有明显不同于块状固体的物理和化学性能,因而呈现出体积效应、表面效应、量子尺寸效应、宏观量子隧道效应等等独特的性能,使得人们把纳米材料科学作为多学科交叉的生长点和跨世纪“热点”的研究领域。把无机纳米粒子Fe3O4 与双歧杆菌胞外多糖结合上,利用纳米粒子对细胞没有毒性或者毒性很小、不易受体内和细胞内各种酶的降解与消化等特点以及由其表面效应产生的巨大的表面能可牢固地吸附生物粒子,从而提高胞外多糖的生物利用率。本课题作为“纳米铁双歧杆菌胞外多糖对胃癌细胞抑制作用与机理的研究”这一国家自然科学基金的子课题,即是制备出Fe3O4 纳米颗粒并对其影响因素予以讨论,从而为抗肿瘤功能性食品及药物的研究开发奠定理论基础。本课题采用共沉淀法制备出Fe3O4纳米颗粒,对其影响因素及其影响原因做以讨论,并采用油酸钠作为表面活性剂进行表面改性处理,对比了未经改性和经油酸钠改性的纳米颗粒的稳定性,主要结果如下: ⑴在制备纳米Fe3O4 的过程中,通氮气的条件至关重要,均匀持续的搅拌是保证颗粒粒径的有效方法,碱溶液的滴加方式对生成的颗粒有着很明显的影响,其制备过程的工艺条件为:制备温度可以取30～50℃之间,反应结束的pH 取10～12 之间,Fe2+/Fe3+=1:2,铁盐的浓度为0.1mol/L,搅拌速度为2000r/min。得到的纳米颗粒粒径为15nm 左右。⑵对Fe3O4 纳米颗粒的分散性进行了研究,超声波虽然能起到一定的分散作用,但其分散能力有限,延长振荡时间超过2min,对分散程度没有太大的改善;用HCl 将pH 值调至3左右,其分散效果比超声波分散效果好,可以采用超声波振荡后在酸性溶液中进行分散。⑶油酸钠是一种阴离子表面活性剂,在酸性条件下有利于其分散。纳米颗粒的改性条件为:pH=5 时,油酸钠的添加量为湿粉质量的20%,添加温度为80℃,得到粒径为15nm 的颗粒。⑷经油酸钠改性的纳米颗粒在较低的浓度、较低的离心速度和pH>6.4 的情况下稳定性较好。纳米颗粒在理化性质发生巨变的同时,生物学效应的性质和强度也可能发生质的变化,其生物安全性正在逐渐受到人们的关注。纳米颗粒的表面积、数目、化学性质、表面包被情况、新鲜度及试验动物的品系、种属等等方面的差异均影响纳米颗粒的毒性作用,本实验将自制的未经改性和经油酸钠改性的Fe3O4纳米颗粒对ICR 小鼠的口服急性毒性进行了研究。得出了以下结论: ⑴改性与未经改性的纳米颗粒配成PVP-40 的胶体溶液,PVP-40 作为对照组,得到ICR小鼠口服的半数致死量LD50均大于3767mg/kg 体重。⑵经两周观察,未见小鼠死亡情况,纳米颗粒对小鼠的肝脏与肺脏均有不同程度的伤害作用,对肝脏的影响较大,且经过改性的纳米颗粒的伤害作用相对较小。更多还原

【Abstract】 Nanosized material is also called ultramicro-particle material, composed of nanoparticles. It neither belongs to micro-system nor macro-system, but between them. It has many particular characterizations, such as volume effect, surface effect, quanta size effect, macroscopical quanta tunnel effect and so on because of its physical and chemical performances different from nubbly solid. Many researches have focused on its application in crossed subject such as bio-medical field. Combining Fe3O4 nanoparticles and exopolysacchrides from bifidobacterium enhances their using efficiency because nanoparticles are little toxical or not and not easily degraded by enzyme and possess good absorption. As a sub-question for discussion of national natural fund, this article was to prepare Fe3O4 nanoparticles and disscuss their influencing factors in order to establish theoretical foundation for anti-cancer and anti-tumour food and medicine. This article focused on the preparation of Fe3O4 nanoparticles by coprecipitation and their modification by sodium oleate. At the same time, the stabilization of non-modified and modified nanoparicle was also studied. The research results obtained were as follows: ⑴Continuous nitrogen and ceaseless agitating and titration method of alkali were all of importance for the well-proportioned size. The technical condition was: temperature was between 30 and 50 centigrade, final pH value was between 10 and 12, the ratio of Fe2+ and Fe3+ was 0.5, concentration of ferrite was 0.1mol/L, stirring velocity was 2000r/min. The size of obtained particles was 15nm. ⑵Dispersive results indicated that ultrasonic had limited separate ability even more than 2 minutes, but acid had better effect at pH value 3. Combining ultrasonic and acid treatment was feasible for better dispersion. ⑶Sodium oleate, as a kind of anion surface active reagent, its modification condition was: pH value was 5, the quantity accounted for 20% of total waterish nanoparticle powder, the temperature was 80 centigrade. ⑷The modified nanoparticles had better stabilities under lower concentration and lower centrifugal rate and pH value higher than 6.4. With the tremendous changes in physi-chemical characterization and property and intensity of bio-effect, the bio-security of nanoparticles have been paid attention to. Many factors such as surface area, amount, chemical characterization, surface-coated condition, freshness and variety and category of experimental animal all affect their toxic intensity. This article studied the acute toxicity of Fe3O4 nanoparticles of non-modified and modified on ICR-mouse by douching stomach. The research results obtained were as follows: ⑴Modified and non-modified nanoparticles were prepared colloid fluid by PVP-40 and their LD50 was higher than 3767mg/kg orally on ICR mouse. ⑵The mice all survived after two weeks. Nanoparticles was harmful to liver and lung to some extent, especially to liver. The modified nanoparticles was little toxical.更多还原