【作者】 艾汉华；

【导师】 黄新堂；

【作者基本信息】 华中师范大学 ， 凝聚态物理， 2008， 博士

【摘要】 双金属氢氧化物（LDHs）,又称为阴离子粘土,由于其独特的亲水性、溶胀性和阴离子可交换性,已经成为一种新型的生物酶分子的固定材料和药物无机载体材料。类水滑石层由共边的M_Ⅱ（OH）₆和M_Ⅲ（OH）₆八面体构成,类似于水镁石的层状结构。阴离子粘土层极带正电荷,层间充填有平衡电荷的阴离子,层间通道中的阴离子是可交换的。我们通过电化学法、水热法、和共沉淀法合成了ZnAl-LDH、NiAl-LDH薄膜与粉体,并用NiAl-LDH粉体修饰玻碳电极,提供了一种廉价、快速、简单的无酶电极制备方法。同时,对ZnAl-LDH作为药物载体进行了前期的毒理研究。具体研究工作集中在如下几个方面:1、用比较简单廉价的电化学法和水热法在铝片和锌片表面制备出纳米水滑石薄膜,用共沉淀法制备出不同二价金属离子组分和相同组分二三价元素不同比例的水滑石纳米粉体。对所制备的纳米水滑石材料进行了形貌、微观结构、成分、热失重和分散性能表征。探讨了纳米水滑石可能的生长机制和对其形貌结构的影响因素。通过实验发现,Zn₃Al₁-LDH和Ni₃Al₁-LDH两种纳米粉体的分散性能良好。2、用表面修饰了纳米水滑石的铝片尝试制备了电化学传感器,对所制备的传感器进行了测试,并对测试结果不理想的原因进行了分析。3、在国际上首次用分散性很好的Ni₃Al₁-LDH纳米粉体与壳聚糖的混合溶液修饰玻碳电极制备出了无酶葡萄糖生物传感器,对制备的生物传感器进行了各种物理和电化学表征,分析了传感器在葡萄糖溶液中的工作机制,给出了传感器在葡萄糖溶液中的浓度校正曲线和人血清葡萄糖实际样品测试的相对误差,并分析了传感器各种可能的影响因素。4、在传感器的优化中,提出利用等离子溅射贵金属的方法来修饰提高传感器的灵敏度,并在有酶和无酶两种传感器上进行了成功的尝试。这种方法的意义在于,当传感器中需要引入金属或合金颗粒时,我们可以通过更换溅射靶材、控制溅射压强和时间的方法获得各种粒径的尺寸均匀的金属或者合金纳米颗粒,解决了传感器在修饰Pt、Au等催化金属时容易引入新的有机或无机无效或有害成分的问题。5、对分散性较好的Zn₃Al₁-LDH用作药物载体进行了前期的毒理研究,通过不同浓度的ZnAl-LDH对Hela细胞的氧化应激系统,DNA断裂,DNA和蛋白质交联,蛋白质羰基含量的影响所做的各种生化测试,显示这种纳米ZnAl-LDH对Hela细胞的氧化应激系统以及对DNA和蛋白质这些生物大分子都不会造成明显的破坏,因此它具有在医药领域应用的潜力。同时,通过Ni₂Al₁-LDH和Ni₃Al₁-LDH两种纳米水滑石的对比测试,分析了纳米水滑石材料的组分与尺寸对细胞生物安全毒性的影响,为下一步的活体测试奠定了基础。不管是共沉淀法合成的Zn₃Al₁-LDH和Ni₃Al₁-LDH,还是等离子溅射获得的Pt纳米颗粒,所有的测试和应用均是在保持纳米材料分散性能的基础上进行的,这也正是我们利用纳米材料独特性能的成功之处。更多还原

【Abstract】 Layered double hydroxides （LDHs）, also called "anionic clays", have been demonstrated as attractive materials for the immobilization of biomolecules and the carrier of drug, due to their hydrophilic, swelling and anion exchange properties. The LDHs consist of M_Ⅱ（OH）₆ and M_Ⅲ（OH）₆ edge-sharing octahedral forming sheets similar to those of brucite. Net positive charges of the layer are balanced by exchangeable anions intercalated between the sheets. We synthesized LDHs （ZnAl-LDH、NiAl-LDH） films and powders via the methods of electrochemistry, hydrothermal and coprecipitation, and our results showed that the modified electrodes in this synthetic lamellar material provides an inexpensive, fast and easy method for the elaboration of electrodes without enzymes. It was a new material to fabricate biosensor. The nanotoxicology of ZnAl-LDH used as drug carrier was discussed. The detailed contents are as follows:（1） The novel inexpensive electrochemical and hydrothermal methods were used to modify Al and Zn substrates with nano-LDH films. The LDHs with different bivalent and trivalent metal ions and with different element ratio were synthesized through coprecipitation method. The morphology, structure, composing and dispersive properties of the LDH nanomaterials were characterized. The growth mechanism and influence of morphology and structure were discussed. The nanomaterials of Zn₃Al₁-LDH and Ni₃Al₁-LDH powders displayed a good dispersive property.（2） The LDH nanoflakes grown on Al substrates were used as electrochemical sensor, and the result were discussed.（3） It is first reported that the glass carbon electrode modified with monodispersed Ni₃Al₁-LDH nanoflakes and chitosan acetum solution was used as glucose biosensor. The working mechanism and concentration calibration curve of biosensor in the glucose solution were characterized with physical and electrochemical methods. The determination of glucose in samples of human serum was performed by the developed biosensor, utilizing both calibration curve and the standard addition method. The diversified influences of biosensor were also discussed.（4） The sensitivity of the developed biosensor modified with Pt nanoparticles by the method of plasma sputtering increased obviously. The size of noble metal nanoparticles could be controlled through controlling the pressure and time of the plasma sputtering.Measurement of oxidative stress was suggested to be one of the best ways to find out if nanomaterials are toxic, and even could find fundamental cause-effect relationship of nanotoxicology. Cells respond to the ZnAl-LDH with different concentration drop in the glutathione （GSH） /oxidized glutathione ratio by mounting protective or injurious responses. We also choose DNA strand break （DSB）, DNA-Protein crosslink （DPC） and carbonyl content in proteins （CCP） as biomonitors. All results demonstrated that ZnAl-LDH nanomaterials should not induce obvious oxidative stress effects of Hela cell system, and it has the potential to be used as drug vehicle in biomedicine field. However further study is still be needed in vivo system.All the applied researches were progressed and based on the monodispersed property of nanomaterials, not only the Zn₃Al₁-LDH and Ni₃Al₁-LDH synthsized via the method of coprecipitation, but also the Pt nanoparticles procured with plasma sputtering. It is the aim that we take advantage of the special properties of nanomaterials.更多还原