Electron Microscopy of Nanostructures in Cells

Nanostructures are small objects with a huge potential. They can be engineered in an endless number of different shapes and sizes and have almost as many future uses. Nanostructures have recently garnered an increasing interest from the life-sciences as nanostructures have the potential to be used in brain-machine interfaces, for drug delivery and for interfacing with cells.

The potential health risks associated with nanostructures are also becoming a more pressing issue with the increased production and use of nanostructures. Developing and testing tools for visualising nanostructures interacting with cells is therefore increasingly more relevant from both an engineering and a toxicological viewpoint.

My work involves developing and exploring electron microscopy (EM) for imaging nanostructures in cells, for the purpose of understanding nanostructure-cell interactions in terms of their possibilities in science and concerns in toxicology. In the present work, EM methods for imaging nanostructure-cell interactions have been explored, and the complex interactions documented and ordered.

In particular the usability of the focused ion beam scanning electron microscope (FIB-SEM) was explored. Using EM techniques, unique images aiding in the interpretation of nanostructure's influence on cells have been provided. For instance, FIB-SEM showcased how nanowires perturbed the nuclear envelope, and helped establish that nanowires can be enveloped by a thin outer membrane deep within the cell.

With respect to the concern of nanostructure toxicology, we have focused on investigating the time effects and visualising the interaction of carbon nanotubes (CNTs) with lung tissue. A basic CNT distribution development model was developed, and the investigations helped verify observations made using single cells in literature.

Furthermore, EM proved valuable as it revealed an unnoticed CNT effect. FIB-SEM helped establish that the effect was linked to eosionophilic crystalline pneumonia (ECP).