Escape route: The laser‐initiated release of fluorescently labeled polymers from polyelectrolyte‐multilayer microcapsules is demonstrated inside living cancer cells. A polymer is incorporated in capsules with metal nanoparticles in their walls, which serve as light‐absorbing centers. The capsules are internalized by cells and near‐infrared light ruptures the walls of the capsules, thus releasing the content into the cells.

Fluchtweg: Die Laser‐initiierte Freisetzung von fluoreszenzmarkierten Polymeren aus Polyelektrolytmultischicht‐Mikrokapseln in lebenden Krebszellen wird vorgestellt. Ein Polymer wird in Kapseln eingeschlossen, die als Lichtabsorptionszentren fungierende Metallnanopartikel in den Wänden enthalten. Die Kapseln werden von Zellen aufgenommen, und Nah‐Infrarotlicht bricht die Kapselwände auf, sodass der Inhalt in die Zellen gelangt.

The spontaneous formation of vortices is a hallmark of collective cellular activity. Here, we study the onset and persistence of coherent angular motion as a function of the number of cells N confined in circular micropatterns. We find that the persistence of coherent angular motion increases with N but exhibits a pronounced discontinuity accompanied by a geometric rearrangement of cells to a configuration containing a central cell. Computer simulations based on a generalized Potts model reproduce the emergence of vortex states and show in agreement with experiment that their stability depends on the interplay of the spatial arrangement and internal polarization of neighboring cells. Hence, the distinct migrational states in finite size ensembles reveal significant insight into the local interaction rules guiding collective migration.