Effects Of Nanoparticles On The Rest Potential Of Aloe Cells

Nanomaterials are a kind of new materials of the21st century. In recent years, with thecommercialization and industrialization of nanoparticles, people have more opportunities toexposed to nanoparticles, they can enter the body of people and animals through manyapproaches, such as breathing and skin touching. Some materials have been applied for a longtime, and no obvious toxic effect has been found. However, when the materials are subdividedinto nanoscale, even if their chemical composition are the same, their physical and chemicalproperties will change greatly and show obvious biological toxicity. So the traditional safetycriteria may be not applicable. Apart from the negative influences founded in humans andanimals, many nanoparticles can also be released into the ecological environment in theprocesses of production and consumption; its ecological toxicity is inevitable. At present,researches of the biological toxicity of nanoparticles have aroused people’s wide attention. Sothis thesis mainly studied the effects of nanoparticles on the rest potential of aloe cellsFirstly, we summarized briefly the research progress and present situation ofnanotoxicology, and then ZnO nanoparticles and Au nanoparticles, which are widely used,were selected to interact with aloe protoplast. Use microelectrode to monitor the rest potentialin real time. ZnO nanoparticles were prepared with sol-gel method, its average particle sizewas3.8nm; Au nanoparticles were prepared with reduction method, its average particle sizewas13.8nm. The tip of the microelectrode, equipped with Ag/AgCl electrode internally andfilled with3mol/L potassium chloride solution, was less than1μm. The linearity of themicroelectrode is tested to be good, and its measurement limit is better than10-9mol/L. Aloecells, with a diameter of about40μm, were obtained by enzymolysis method, their activitywere detected by FDA staining. The rest potential, as detected by microelectrode, was-6~-15mV. Its amplitude remained unchanged when the cell membrane is intact. However, when themembranes ruptured, the rest potential disappeared immediately. ZnO nanoparticles and Aunanoparticles were added into the medium, respectively, to obtain30mg/L,60mg/L ZnOsuspension and25mg/L Au suspension. The cells were respectively dropped into thesesuspensions, and their rest potentials were immediately tested. It was found that, ZnO and Aunanoparticles had no obvious effects on the amplitude of rest potential when the cells werealive. But when the cells ruptured to die, rest potential disappeared. However the addition ofZnO and Au nanoparticles accelerated the death of the cells and shortened the duration of therest potential. The above result is of great importance to future investigations of theinteractions between cells and nanoparticles with ion-selective microelectrodes. What’s more,it will be also helpful for the establishment of new biological safety evaluation criteria.