An DNA Sensor-based Assay to Measure Receptor-specific Adhesion Forces of Eukaryotic Cells and Pathogens.

Motility of eukaryotic cells or pathogens within tissues is mediated by the turnover of specific interactions with other cells or with the extracellular matrix. Biophysical characterization of these ligand-receptor adhesions helps to unravel the molecular mechanisms driving migration. Traction force microscopy or optical tweezers are typically used to measure the cellular forces exerted by cells on a substrate.

An Engineered Biomimetic Peptide Regulates Cell Behavior by Synergistic Integrin and Growth Factor Signaling.

Recreating the healing microenvironment is essential to regulate cell-material interactions and ensure the integration of biomaterials. To repair bone, such bioactivity can be achieved by mimicking its extracellular matrix (ECM) and by stimulating integrin and growth factor (GF) signaling. However, current approaches relying on the use of GFs, such as bone morphogenetic protein 2 (BMP-2), entail clinical risks.

Forces during cellular uptake of viruses and nanoparticles at the ventral side.

Many intracellular pathogens, such as mammalian reovirus, mimic extracellular matrix motifs to specifically interact with the host membrane. Whether and how cell-matrix interactions influence virus particle uptake is unknown, as it is usually studied from the dorsal side. Here we show that the forces exerted at the ventral side of adherent cells during reovirus uptake exceed the binding strength of biotin-neutravidin anchoring viruses to a biofunctionalized substrate.

Selective binding and lateral clustering of α5β1 and αvβ3 integrins: Unraveling the spatial requirements for cell spreading and focal adhesion assembly.

Coordination of the specific functions of α5β1 and αvβ3 integrins is crucial for the precise regulation of cell adhesion, spreading and migration, yet the contribution of differential integrin-specific crosstalk to these processes remains unclear. To determine the specific functions of αvβ3 and α5β1 integrins, we used nanoarrays of gold particles presenting immobilized, integrin-selective peptidomimetic ligands. Integrin binding to the peptidomimetics is highly selective, and cells can spread on both ligands.

Soft/elastic nanopatterned biointerfaces in the service of cell biology.

Engineering of biomimetic interfaces has become a valuable tool for guiding cellular processes such as adhesion, spreading, motility, as well as proliferation, differentiation, and apoptosis. The interaction of cells with the extracellular matrix (ECM) or with other cells is involved in nearly every cellular response in vivo. Recent wide-ranging evidence shows that crosstalk between different environmental stimuli can have a tremendous impact on various cell functions.

Light- and transmission-electron-microscopic investigations on distribution of CD44, connexin 43 and actin cytoskeleton during the foreign body reaction to a nanoparticular hydroxyapatite in mini-pigs.

Foreign body giant cells (FBGCs) are formed by fusion of mononucleated macrophages during the foreign body response to a nanoparticulate hydroxyapatite (HA) implanted in defects of mini-pig femura. The molecular mechanisms underlying the formation of FBGCs are still largely obscure. Here we propose connexin 43 (cx43) and CD44 as candidate molecules involved in the fusion process.

Force-induced destabilization of focal adhesions at defined integrin spacings on nanostructured surfaces.

Focal adhesions are the anchoring points of cells to surfaces and are responsible for a large number of surface sensing processes. Nanopatterning studies have shown physiological changes in fibroblasts as a result of decreasing density of external binding ligands. The most striking of these changes is a decreased ability to form mature focal adhesions when lateral ligand distances exceed 76 nm.

Cell adhesion and polarisation on molecularly defined spacing gradient surfaces of cyclic RGDfK peptide patches.

In vivo cell migration and location are orchestrally guided by soluble and bound chemical gradients. Here, gradients of extracellular matrix molecules are formed synthetically by the combination of a surface nanopatterning technique called block copolymer nanolithography (BCN) and a biofunctionalisation technique. A modified substrate dip-coating process of BCN allows for the formation of precise molecular gradients of cyclic RGDfK peptide patches at interfaces, which are presented to cells for testing cell adhesion and polarisation.