Project ID Assignment: ENM-6: Relationships Between ENM Geometry on Biological Outcomes :
Nanowires
Jeffrey I. Zink
Abstract: Interest in high aspect ratio nanomaterials evolved from the history of fiber toxicology. High
aspect ratio materials such as asbestos, carbon nanotubes and TiO2 nanowires lead to frustrated
phagocytosis and inflammatory responses in cells. However most research only explored a very limited
number of lengths and aspect ratios, and it is therefore not clear what is the critical length and aspect
ratio that can induce such an effect. To address this question, we will synthesize a cerium oxide (CeO2)
nanorod library with a wide range of aspect ratios. The advantage of using CeO2 is that it is biologically
inert, and thus studies of the length and aspect ratio will not be complicated by intrinsic toxicity. By
controlling the hydrothermal synthesis composition and conditions, CeO2 nanorods and nanowires with
precisely controlled lengths and aspect ratios will be made. Preliminary results show that nanorods
obtained with the CeCl3 concentration varying by a factor of ten while keeping other synthesis
composition and conditions constant range in length from 110 to 30 nm (with a constant diameter). The
aspect ratios will be further tuned by adjusting the other synthesis parameters. The successful creation
of nanorod/nanowire combinatorial libraries will allow a pure length and aspect ratio effect on
biological response to be studied in a systematic manner. We will also synthesize other nanowire
libraries of materials such as vanadia and manganese oxide to attempt to further demonstrate that
nanowire length plays an important role in high aspect ratio nanomaterial toxicity.