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Cell adhesion is regulated by molecularly defined protein interactions and by mechanical forces, which can activate a dynamic restructuring of adhesion sites. Previous attempts to explore the response of cell adhesion to forces have been limited to applying mechanical stimuli that involve the cytoskeleton. In contrast, we here apply a new, oscillatory type of stimulus through push-pull azobenzenes. Push-pull azobenzenes perform a high-frequency, molecular oscillation upon irradiation with visible light that has frequently been applied in polymer surface relief grating. We here use these oscillations to address single adhesion receptors. The effect of molecular oscillatory forces on cell adhesion has been analyzed using single-cell force spectroscopy and gene expression studies. Our experiments demonstrate a reinforcement of cell adhesion as well as upregulated expression levels of adhesion-associated genes as a result of the nanoscale 'tickling' of integrins. This novel type of mechanical stimulus provides a previously unprecedented molecular control of cellular mechanosensing. [ABSTRACT FROM AUTHOR]

Diblockcopolymer micelle nanolithography (BCML) is a versatileand efficient method to cover large surface areas with hexagonallyordered arrays of metal nanoparticles, in which the nanoparticlesare equally spaced. However, this method falls short of providinga controlled allocation of such regular nanoparticle arrays with specificspacing into micropatterns. We present here a quick and high-throughputmethod to generate quasi-hexagonal nanoparticle structures with well-definedinterparticle spacing on segments of nanotopographic Si substrates.The topographic height of these segments plays a dominant role indictating the spacing between the gold nanoparticles, as the nanoparticlearrangement is controlled by immersion forces and by their self-assemblywithin the segments. Our novel strategy of employing a single-stepBCML routine is a highly promising method for the fabrication of regulargold nanopatterns in micropatterns for a wide range of applications. [ABSTRACT FROM AUTHOR]