Cell membrane topology analysis by RICM enables marker-free adhesion strength quantification.

Reflection interference contrast microscopy (RICM) allows the visualization of the cell's adhesion topology on substrates. Here it is applied as a new label-free method to measure adhesion forces between tumor cells and their substrate without any external manipulation, i.e.

Marker-free phenotyping of tumor cells by fractal analysis of reflection interference contrast microscopy images.

Phenotyping of tumor cells by marker-free quantification is important for cancer diagnostics. For the first time, fractal analysis of reflection interference contrast microscopy images of single living cells was employed as a new method to distinguish between different nanoscopic membrane features of tumor cells. Since tumor progression correlates with a higher degree of chaos within the cell, it can be quantified mathematically by fractality.

The role of integrin-linked kinase in the molecular architecture of focal adhesions.

Integrin-mediated focal adhesions (FAs) are large, multi-protein complexes that link the actin cytoskeleton to the extracellular matrix and take part in adhesion-mediated signaling. These adhesions are highly complex and diverse at the molecular level; thus, assigning particular structural or signaling functions to specific components is highly challenging. Here, we combined functional, structural and biophysical approaches to assess the role of a major FA component, namely, integrin-linked kinase (ILK), in adhesion formation.

Dissecting the molecular architecture of integrin adhesion sites by cryo-electron tomography.

Focal adhesions are integrin-based multiprotein complexes, several micrometres in diameter, that mechanically link the extracellular matrix with the termini of actin bundles. The molecular diversity of focal adhesions and their role in cell migration and matrix sensing has been extensively studied, but their ultrastructural architecture is still unknown. We present the first three-dimensional structural reconstruction of focal adhesions using cryo-electron tomography.

Cell adhesion and response to synthetic nanopatterned environments by steering receptor clustering and spatial location.

During adhesion and spreading, cells form micrometer-sized structures comprising transmembrane and intracellular protein clusters, giving rise to the formation of what is known as focal adhesions. Over the past two decades these structures have been extensively studied to elucidate their organization, assembly, and molecular composition, as well as to determine their functional role. Synthetic materials decorated with biological molecules, such as adhesive peptides, are widely used to induce specific cellular responses dependent on cell adhesion.

A crucial role for primary cilia in cortical morphogenesis.

Primary cilia are important sites of signal transduction involved in a wide range of developmental and postnatal functions. Proteolytic processing of the transcription factor Gli3, for example, occurs in primary cilia, and defects in intraflagellar transport (IFT), which is crucial for the maintenance of primary cilia, can lead to severe developmental defects and diseases. Here we report an essential role of primary cilia in forebrain development.

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.

Induction of cell polarization and migration by a gradient of nanoscale variations in adhesive ligand spacing.

Cell interactions with adhesive surfaces play a vital role in the regulation of cell proliferation, viability, and differentiation, and affect multiple biological processes. Since cell adhesion depends mainly on the nature and density of the adhesive ligand molecules, spatial molecular patterning, which enables the modulation of adhesion receptor clustering, might affect both the structural and the signaling activities of the adhesive interaction. We herein show that cells plated on surfaces that present a molecularly defined spacing gradient of an integrin RGD ligand can sense small but consistent differences in adhesive ligand spacing of about 1 nm across the cell diameter, which is approximately 61 mum when the spacing includes 70 nm.