Micropatterned substrates can be used to study the processes involved in cell adhesion and spreading. In addition, this approach has provided insight into the role of the spatial arrangement of cell–matrix adhesions with regards to numerous cellular functions, including migration, division and differentiation. However, one of the drawbacks of fixed micropatterned substrates is that they do not allow the study of the cellular changes in response to the remodelling of the extracellular environment. To overcome this problem, Manuel Théry and colleagues (p. ) have developed a new laser-based technique that makes it possible to study cytoskeletal modifications in real time in response to changes in the micropattern. Using a tightly focused pulsed laser, they ablate the polyethylene glycol coating near a cell that has adhered to a specific micropattern. The subsequent adsorption of adhesive proteins to the ablated spots creates additional adhesion sites for the cells. To test this system, the researchers investigate the distances between individual adhesion sites that are required for cell extension or contraction and show that this technique can be used to dynamically remodel the actin cytoskeleton. They conclude that this approach offers a versatile way to study how small-scale changes in the micro-environment affect cellular responses.
