Description:
The cover picture shows the first demonstration of cell adhesion activation through a nanoadhesive pattern with single integrin resolution. Scanning electron microscopy images nanoscopic 6‐nm large Au particles as white dots, which are functionalized with cell ligands and organized in a square pattern. The free glass substrate area between the Au is covered with a biologically inert polymer, thereby avoiding protein or cell interactions with the glass. A few cell lamellipodia experience this environment and adhere entirely to the Au–nanoparticle pattern squares. The substrate forms a well‐defined, rigid adhesion pattern where Au particles control integrin–integrin interactions in focal adhesions by their separation distance. A separation between single intergrins of ≥73 nm results in limited cell attachment and spreading, and dramatically reduces the formation of focal adhesion and actin stress fibers. The range of 58–73 nm is found to be a universal length scale for integrin clustering and activation, since these properties are shared by a variety of cultured cells. Find out more in the Communication by Spatz et al. on page 383.