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Wolfgang Eck

Publications and source records attributed to Wolfgang Eck.

4 recordsLinked to original sources
PubMed2004

Protein deformation of lipid hybrid bilayer membranes studied by sum frequency generation vibrational spectroscopy.

Structural deformations of lipid hybrid bilayer membranes induced by signal peptideless (SPL) proteins have been studied for the first time using the inherently surface specific nonlinear optical technique of sum frequency generation vibrational spectroscopy. Specifically, deformations of 1,2-distearoylphosphatidylglycerol(DSPG) membranes induced by interaction with FGF-1, a SPL protein which is released asa function of cellular stress through a nonclassical pathway, have been investigated. FGF-1 was found to induce lipid alkyl chain deformations in previously highly ordered DSPG membranes at the extremely low concentration of 1 nM at 60 degrees C. The deformation process was shown to exhibit a degree of reversibility upon removal of the protein by rinsing with buffer solution.

Fibroblast Growth Factor 1↗
PubMed2004

Activation of integrin function by nanopatterned adhesive interfaces.

To study the function behind the molecular arrangement of single integrins in cell adhesion, we designed a hexagonally close-packed rigid template of cell-adhesive gold nanodots coated with cyclic RGDfK peptide by using block-copolymer micelle nanolithography. The diameter of the adhesive dots is < 8 nm, which allows the binding of one integrin per dot. These dots are positioned with high precision at 28, 58, 73, and 85 nm spacing at interfaces. A separation of > or = 73 nm between the adhesive dots results in limited cell attachment and spreading, and dramatically reduces the formation of focal adhesion and actin stress fibers. We attribute these cellular responses to restricted integrin clustering rather than insufficient number of ligand molecules in the cell-matrix interface since "micro-nanopatterned" substrates consisting of alternating fields with dense and no nanodots do support cell adhesion. We propose that the range between 58-73 nm is a universal length scale for integrin clustering and activation, since these properties are shared by a variety of cultured cells.

Cell Adhesion↗
PubMed2003

Factors that determine the protein resistance of oligoether self-assembled monolayers --internal hydrophilicity, terminal hydrophilicity, and lateral packing density.

Protein resistance of oligoether self-assembled monolayers (SAMs) on gold and silver surfaces has been investigated systematically to elucidate structural factors that determine whether a SAM will be able to resist protein adsorption. Oligo(ethylene glycol) (OEG)-, oligo(propylene glycol)-, and oligo(trimethylene glycol)-terminated alkanethiols with different chain lengths and alkyl termination were synthesized as monolayer constituents. The packing density and chemical composition of the SAMs were examined by XPS spectroscopy; the terminal hydrophilicity was characterized by contact angle measurements. IRRAS spectroscopy gave information about the chain conformation of specific monolayers; the amount of adsorbed protein as compared to alkanethiol monolayers was determined by ellipsometry. We found several factors that in combination or by themselves suppress the protein resistance of oligoether monolayers. Monolayers with a hydrophobic interior, such as those containing oligo(propylene glycol), show no protein resistance. The lateral compression of oligo(ethylene glycol) monolayers on silver generates more highly ordered monolayers and may cause decreased protein resistance, but does not necessarily lead to an all-trans chain conformation of the OEG moieties. Water contact angles higher than 70 degrees on gold or 65 degrees on silver reduce full protein resistance. We conclude that both internal and terminal hydrophilicity favor the protein resistance of an oligoether monolayer. It is suggested that the penetration of water molecules in the interior of the SAM is a necessary prerequisite for protein resistance. We discuss and summarize the various factors which are critical for the functionality of "inert" organic films.

Adsorption↗