Engineered nanomaterials (ENMs) have been widely used in food, personal care products, biomedicines, industry and agriculture for their unique physical and chemical properties, resulting in increasing human and environmental exposure to ENMs. ENMs entering the human body through personal care products will inevitably interact with biological fluids, changing the chemical form of ENMs, and thus affecting the health risks of ENMs. Currently, nano-silver and nano-zinc oxide are widely used in personal care products for their excellent antibacterial properties. However, the research on the chemical stability of silver and zinc oxide nanoparticles in tear fluids is rather little. As a result, the potential health risks of silver and zinc oxide nanoparticles cannot be evaluated in an objective and more comprehensive manner.
To address the above-mentioned problems, Li Lingxiangyu, et al. from the Lab of Professor Wang Yawei of the School of Environment, Hangzhou Institute for Advanced Study (HIAS), UCAS has made new research progress in the chemical transformation and risks of silver and zinc oxide nanoparticles. Their research result, i.e. Emerging Investigator Series: Chemical Transformation of Silver and Zinc Oxide Nanoparticles in Simulated Human Tear Fluids: Influence of Biocoronae, has been published as a cover article in the Environmental Science: Nano of RSC (IF: 8.131), and has been included in the Emerging Investigator Series (Figure 1).
Figure 1: The Work has been Selected as A Cover Article in Environmental Science: Nano
In this research, silver and zinc oxide nanoparticles are selected as typical ENMs to study their chemical transformation processes in simulated human tear fluids and to preliminarily evaluate the influence of the transformation on the antibacterial properties of nanomaterials. The results show that protein, an important part of tear fluids, is the key to the chemical stability of silver and zinc oxide nanoparticles. That is, in tear fluids containing protein, silver and zinc oxide nanoparticles always maintain high chemical stability without chemical transformation. However, in tear fluids without protein, silver nanoparticles transform into silver chloride, and zinc oxide nanoparticles gradually transform into basic zinc carbonate. This is mainly because proteins form a layer of protein corona on the surface of the nanomaterials, blocking silver and zinc oxide nanoparticles from contacting other components in the tear fluids, thus completely inhibiting the chemical transformation of the nanomaterials. The transformation of silver nanoparticles into silver chloride can enhance the antibacterial properties, while the transformation of zinc oxide nanoparticles into basic zinc carbonate can weaken the antibacterial properties. This research clarifies the influence of protein corona on the chemical transformation of nanomaterials in biological fluids. On this basis, the research on the environmental processes and health risks of nanomaterials in the future can target the important micro-interface of corona.
Figure 2Morphological Distribution of Silver and Zinc Oxide Nanoparticles in Simulated Human Tear Fluids: (a) Silver Nanoparticles; (b) Zinc Oxide Nanoparticles (in the figure, STF-1 represents tear fluids containing protein; STF-2 represents tear fluids without protein)
This work was supported by the National Natural Science Foundation of China.
Article link:https://pubs.rsc.org/mlb/content/articlelanding/2021/en/d1en00566a#!ihlk
