Apr 23, 2009
AFM reveals "hidden" differences between normal and cancerous cells
Using an atomic force microscope, researchers at Clarkson University in New York have identified an important difference in the surface properties of normal and cancer cells. Igor Sokolov and colleagues have found that normal cells have "brushes" of one length on their surface while cancerous cells have two brush lengths that have very different densities to the brushes on normal cells. This important variation means that cancer and normal cells may interact very differently with nanoparticles, something that could be exploited for cancer detection and treatment via drug delivery.
Cancer cells are unlike normal cells in many ways. For example, they have different mechanical properties and adhere to other cells and the extracellular matrix in a different way. The variation in cell surface "brushes" revealed by Sokolov's team is almost impossible to quantify with other microscopic methods, such as optical or electron microscopy. The brushes consist mostly of microridges and tiny "hairs", microvilii, which are needed for cells to interact with their environment.
The Clarkson team obtained its results by analysing force measurements taken from the cell surface using an atomic force microscope (AFM). By analysing the deformation curves, the researchers found a two-layer behaviour in the cells. They then developed a model to decouple these two layers so that they could study them separately.
"Normal cells and cancer cells should interact very differently with micro- and nanoparticles because of the differences in their surface geometries," Sokolov told nanotechweb.org. "This phenomenon could be used for cancer detection and potential treatment through drug delivery." For example, fluorescent silica particles might be employed to detect cancer cells, he explains.
The team now plans to develop a better model so that more-precise surface features can be detected. The researchers also hope that biologists will make more use of AFM techniques to discern features like brushes on cells. "A lot of biologists think that the AFM is very limited for use in their subject field but our work shows that it has much, hitherto hidden, potential," added Sokolov.
The work was published in Nature Nanotechnology.
About the author
Belle Dumé is contributing editor at nanotechweb.org