No abstract

Cell adhesion is regulated by molecularly defined protein interactions and by mechanical forces,w hichc an activate ad ynamic restructuring of adhesion sites.P revious 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 anew,oscillatory type of stimulus through push-pull azobenzenes.P ush-pull azobenzenes perform ah igh-frequency,m olecular 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.T he effect of molecular oscillatory forces on cell adhesion has been analyzed using single-cell force spectroscopyand gene expression studies.O ur experiments demonstrate ar einforcement of cell adhesion as well as upregulated expression levels of adhesion-associated genes as ar esult of the nanoscale "tickling" of integrins.T his novel type of mechanical stimulus provides ap reviously unprecedented molecular control of cellular mechanosensing.

Localized plasmon resonance (LSPR) spectroscopy, employing gold nanodisk substrates, is applied for studies of photoswitching in self-assembled monolayers of azobenzene-containing thiols. By choosing customized samples in which the sharp LSPR resonance is well separated from the spectral regime of the molecular absorption bands, the photoisomerization kinetics of the adlayer can be monitored in real time. Quantitative data on the photoinduced trans-cis and cis-trans isomerization processes in inert gas atmosphere were obtained as a function of irradiation intensity and temperature, demonstrating the high sensitivity of this technique to such processes in functional adlayers.

Cell adhesion is regulated by molecularly defined protein interactions and by mechanical forces,w hichc an activate ad ynamic restructuring of adhesion sites.P revious 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 anew,oscillatory type of stimulus through push-pull azobenzenes.P ush-pull azobenzenes perform ah igh-frequency,m olecular 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.T he effect of molecular oscillatory forces on cell adhesion has been analyzed using single-cell force spectroscopyand gene expression studies.O ur experiments demonstrate ar einforcement of cell adhesion as well as upregulated expression levels of adhesion-associated genes as ar esult of the nanoscale "tickling" of integrins.T his novel type of mechanical stimulus provides ap reviously unprecedented molecular control of cellular mechanosensing.