02.08.2010

Nanomechanics of Collagen Fibrils

Collagen is the most abundant protein in the human or animal body. It is found in ligaments, tendons, skin, cartilage, bones, cornea, sclera (white of the eye), and blood vessels to name but a few. All of these tissues are biomechanically important; therefore, knowing the mechanical properties of collagen at all hierarchical levels or length-scales is of critical importance. Our studies have concentrated on the mechanics of collagen fibrils from bovine Achilles tendon, which is a self-assembly of aligned monomeric tropocollagen molecules. more25.06.2010

AFM and Combined Optical Techniques

This article briefly describes the basics of both optical and atomic force microscopy, followed by a discussion of some of the technical challenges of integrating these two distinct imaging modalities. In certain cases, the benefits and disadvantages of different approaches to design and integration are discussed. Lastly, a few examples of successful application of these combined imaging modalities are presented.

Introduction
more30.12.2009

The Dynamic of Synthetic Proteo-nucleic Complexes

Synthetic proteo-nucleic structures (PDNA) encompassing a ss-DNA sequence covalently attached to a cytochrome b5-derived protein domain through a synthetic linker were designed. PDNAs can bind to natural or supported membranes through an histidine-tag-nickel-NTA modified phospholipids. Alternatively the structures can be attached, while keeping free lateral diffusion capabilities, by interaction of the protein his-tag with a substrate supported field of nickel ions. more29.12.2009

Optical Tweezers

The propulsion of the leading edge of neuronal lamellipodia is a complex process in which the polymerization of actin filaments towards the cell membrane is a major component [1,2]. This process is at the origin of force generation in neurons. By using optical tweezers, we have characterized the dynamics by which lamellipodia of Dorsal Root Ganglia neurons exerted force on encountered obstacles such as silica beads. more28.12.2009

AFM-studies on Solid Supported Lipid-bilayers with Bound Proteins

Proteins are involved in all processes which are necessary for living, e.g. they are responsible for growth and cleavage of cells, which makes them an interesting topic for science and medical application. Small GTPases, like Ras, are GTP-binding proteins involved in cellular processes, e.g. vesicle transport, cell cycles, nuclear import and signal transduction. GTPases act as molecular switches, which cycle between a GDP-bound inactive and a GTP-bound active state regulated through different factors. In oncogenic mutants of Ras this regulation is disturbed. more23.12.2009

Determination of Physical Properties of a Single Peptide by AFM Experiments

By stretching a polymer in solution using single molecule techniques it is possible to infer about its physical properties. In particular, AFM stretching experiments allow for a full characterization of the elasto-mechanical properties of the sample under study, taking into account both statical and dynamical regimes [1]. In the presented work, single molecule AFM force spectroscopy experiments have been used to determine mechanical properties of a polymer obtained starting from the Exon 28 (Ex28) of the human elastin gene. more22.12.2009

Multiple Facets of Neuronal Growth

A prerequisite for an understanding of the mechanisms of nerve regeneration and neuronal development is the understanding of the principles of force generation in growth cones - the mechanical and chemical sensor of a neuron. In our working group we try to approach this issue from a variety of different aspects, combining experimental and theoretical studies of actin networks, membrane fluctuations and focal adhesion sites. more21.12.2009

Cell Adhesion on Micro-Nanostructured Surfaces

Motivation:
Many aspects of cellular adhesion to the surrounding, the extracellular matrix (ECM), are of great interest as they control and influence various fundamental cell actions such as motility, differentiation, proliferation and apoptosis and hence, even the function of an organism may depend on this complex and highly regulated process. more