Scientists have identified a critical difference between the mechanical properties of normal and cancer cells ― variation in brushes or tiny hairs on the cell surface. The discovery, reported online this week in Nature Nanotechnology, suggests new considerations when studying cancerous cells using the atomic force microscope, a high-resolution microscope commonly used to study morphology and mechanics of cells.

It is well known that cancerous cells have different mechanical and adhesion properties from normal cells, but the reasons for this have so far been unclear.

Brushes on the cell surface, mostly consisting of microridges and tiny hairs called microvilli, are important for interacting with the external environment. Igor Sokolov and colleagues processed force measurements ― taken from the cell surface using an atomic force microscope ― according to a model that accounts for these brushes, to show quantitatively that cancerous cells are different. Normal cells have brushes of one length, whereas cancerous cells have mostly two brush lengths of significantly different densities.

The authors suggest that the difference in the brush layers may have a biological significance and should be considered when characterizing cells by mechanical methods using the atomic force microscope.