AVS 58th Annual International Symposium and Exhibition
    Helium Ion Microscopy Focus Topic Wednesday Sessions
       Session HI+AS+BI+NS-WeM

Paper HI+AS+BI+NS-WeM11
Imaging and Characterizing Cellular Interaction of Nanoparticles using Helium Ion Microscopy

Wednesday, November 2, 2011, 11:20 am, Room 106

Session: Nano- and Bio- Imaging with Helium Ion Microscopy
Presenter: Bruce Arey, Pacific Northwest National Laboratory
Authors: B.W. Arey, Pacific Northwest National Laboratory
V. Shutthanandan, Pacific Northwest National Laboratory
Y. Xie, Pacific Northwest National Laboratory
A. Tolic, Pacific Northwest National Laboratory
G. Orr, Pacific Northwest National Laboratory
Correspondent: Click to Email
The helium ion mircroscope (HeIM) probes light elements (e.g. C, N, O, P) with high contrast due to the large variation in secondary electron yield, which minimizes the necessity of specimen staining. A defining characteristic of HIM is its remarkable capability to neutralize charge by the implementation of an electron flood gun, which eliminates the need for coating non-conductive specimens for imaging at high resolution. In addition, the small convergence angle in HeIM offers a large depth of field (~5x FE-SEM), enabling tall structures to be viewed in focus within a single image. Taking advantage of these capabilities, we investigate the interactions of engineered nanoparticles (NPs) at the surface of alveolar type II epithelial cells grown in culture. The increasing use of nanomaterials in a wide range of commercial applications has the potential to increase human exposure to these materials, but the impact of such exposure on human health is still unclear. One of the main routs of exposure is the respiratory tract, where alveolar epithelial cells present a vulnerable target. Since the cellular interactions of NPs govern the cellular response and ultimately determine the impact on human health, our studies will help delineating relationships between particle properties and cellular interactions and response to better evaluate NP toxicity or biocompatibility.

The Rutherford backscattered ion (RBI) is a helium ions imaging mode, which backscatters helium ions from every element except hydrogen, with a backscatter yield that depends on the atomic number of the target. Energy-sensitive backscatter analysis is being developed, which when combined with RBI image information, support elemental identification at helium ion submicron resolution. This capability will enable distinguishing NPs from cell surface structures with nanometer resolution.