Silver's Shape Does Matter!

By: Melissa Bracero

Figure 1: Set of TEM images of silver nanomaterials. A) Spherical silver nanoparticles. B) Silver nanocubes. C) Silver nanowires. 

Silver, a commonly used nanomaterial, is used in plenty of consumer goods like athletic clothing, toys, food storage containers, and wound wrappings. There has been a lot of work in studying toxicity of silver nanomaterials, but not enough in studying shape-based toxicity. In this experiment, spherical silver nanoparticals, silver nanocubes and silver nanowires are tested through multiple methods. These include silver nanomaterial synthesis, nanomaterial characterization, plant toxicity measurements using Lolium mutiforum, bacterial tests (3 different bacteria) and statistical analysis. Each silver shape had same surface coating and the size was kept constant, in order to properly compare to each other. The results showed that shape of nanomaterials can affect toxicity. Silver nanocubes are less toxic towards plants than spherical silver nanoparticles, but had similar bacterial toxicity. This article suggests that effective shape engineering could allow for desired properties of silver nanomaterials, all while avoiding unwanted side effects in the environment. However, shape is not the only factor that contributes to the final toxicity of nanomaterial in the environment. Yet, having shape control and an understand of shape-depended properties of silver nanomaterials is an area that can bring many surprises to science.

Reference

 

Gorka, D. E., Osterberg, J. S., Gwin, C. A., Colman, B. P., Meyer, J. N., Bernhardt, E. S., . . . Liu, J. (2015). Reducing Environmental Toxicity of Silver Nanoparticles through Shape Control. Environmental Science & Technology Environ. Sci. Technol., 49(16), 10093-10098. doi:10.1021/acs.est.5b01711