Biomembrane interactions in the toxicology of nanoparticles to microorganisms

纳米粒子和纳米材料在现代生活中的应用越来越广泛。然而，人们担心它们对生态系统和相关生物体的影响，以及可能对人类健康直接和间接的有害影响。这是非常重要的，因为纳米粒子的物理和化学是相当反常的。纳米颗粒的大小意味着它们在水体系中的行为介于溶解和颗粒物质之间。这也适用于它们与生物有机体的相互作用和可能的积累。这项建议是一项试点研究，试图解决这些问题。我们建议使用两个简单但完善的基本模型，以更深入地了解通常被认为是安全的纳米颗粒和纳米材料的生物活性和生物累积。本研究的目的是评估纳米颗粒的生物学反应机制，细胞膜在该过程中的参与，以及该机制与纳米颗粒在培养梅达中的物理化学特性的关系。经典的膜电化学模型组成的磷脂单层汞电极将被用来评估推定的生物膜活性的纳米粒子。细菌生物测定方法将用于蓝细菌培养物，以评估纳米颗粒的生物活性和生物累积性。两个模型的两个系列实验将密切协调。研究的大部分将用于：（i）表征纳米颗粒的粒径，形状，表面电荷，晶体结构和组成，最初和加入培养基时，特别注意其分散特性，（ii）研究纳米颗粒对模型生物膜系统的影响，（iii）研究纳米颗粒对蓝藻培养物活力的影响。在这些初始实验中，电化学和生物测定实验都将在缓冲培养基中进行。其目的是测试的假设，即生物膜是至关重要的机制的毒性的纳米粒子在研究结束时，我们应该已经制定了一个协议的基础上，这一假设有关的生物活性的纳米粒子对蓝藻的物理和化学功能。

Nanoparticles and nanomaterials are having in increasing application in modern life. There are concerns however about their effect on the ecosystem and associated organisms and possible harmful effects directly and indirectly on human health. This is very important because the physics and chemistry of nanoparticles is rather anomalous. The size of nanoparticles means that their behaviour in aqueous systems lies somewhere in between dissolved and particulate species. This will also apply to their interaction with and possible accumulation by biological organisms. This proposal is a pilot study which attempts to address these issues. We propose to use two simple but well established, fundamental models to obtain a deeper understanding of the biological activity and bioaccumulation of nanoparticles and nanomaterials which are generally considered as safe. The objective of the study is to evaluate the mechanism of the biological response to the nanoparticles, the involvement of the cell membrane in the process and the relationship of the mechanism to the physical chemical characteristics of the nanoparticles in the culture meda. The classical membrane electrochemical model consisting of a phopholipid monolayer on a mercury electrode will be employed to evaluate the putative biomembrane activity of the nanoparticles. A bacterial bioassay method will be used with cultures of cyanobacteria to assess the biological activity and the bioaccumulation of the nanoparticles. Both series of experiments on the two models will be closely coordinated. The bulk of the study will be spent:(i) Characterising the nanoparticles with respect to their particle size, shape, surface charge, crystal structure and composition both initially and when added to culture medium with particular attention to their properties in dispersion, (ii)Studying the effects of the nanoparticles on a model biological membrane system, (iii) Studying the effects of the nanoparticles on the viability of cyanobacterial cultures. In these initial experiments both the electrochemical and bioassay experiments will be carried out in a buffered culture medium. The aim is to test the hypothesis that the biological membrane is critical in the mechanisms of toxicity of the nanoparticles At the end of the study we shall have developed a protocol based on this hypothesis for relating the biological activity of nanoparticles towards cyanobacteria to their physical and chemical functionality.