相关论文: Atomic Force Microscopy of height fluctuations of …
We report the phenomenon of periodic shape oscillations occurring in 3T3 fibroblasts merely as a consequence of a loss of cell-substrate adhesion. The oscillatory behavior can last many hours at a constant frequency, and can be switched off…
Polymerization of actin proteins into dynamic structures is essential to eukaryotic cell life. This has motivated a large body of in vitro experiments measuring polymerization kinetics of individual filaments. Here we model these kinetics,…
We present a contactless method for measuring the elastic modulus of living cells (human triple-negative breast cancer, MDA-MB-231) from the thermal fluctuations of an atomic force microscope (AFM) cantilever. By analyzing the power…
We study force generation by a set of parallel actin filaments growing against a non-rigid obstacle, in presence of an external load. The filaments polymerize by either moving the whole obstacle, with a large energy cost, or by causing…
Numerous cell types relate to their immediate environment by exerting a three-dimensional pressure field on their environment, with components both longitudinal and transverse to the cell membrane. This pressure field can in principle be…
Direct correlation between temporal structural fluctuations and electron wind force is demonstrated, for the first time, by STM imaging and analysis of atomically-resolved motion on a thin film surface under large applied current (10e5…
We show that in experimental atomic force microscopy studies of the lifetime distribution of mechanically stressed folded proteins the effects of externally applied fluctuations can not be distinguished from those of internally present…
In this work, we study in detail the distribution of stochastic forces generated by the molecular motors activity, in the actin cortex of pre-muscular cells. By combining active and passive rheology experiments, performed on the same…
Amplitude-modulation atomic force microscopy enables observation of fragile molecules at the nanometer scale. To shorten measurement times and capture dynamic molecules, increasing the frame rate is essential. Traditionally, maximum frame…
The growth of actin filament networks is a fundamental biological process that drives a variety of cellular and intracellular motions. During motility, eukaryotic cells and intracellular pathogens are propelled by actin networks organized…
Living cells exhibit an important out-of-equilibrium mechanical activity, mainly due to the forces generated by molecular motors. These motor proteins, acting individually or collectively on the cytoskeleton, contribute to the violation of…
The polymerization of actin via branching at a cell membrane containing nucleation-promoting factors is simulated using a stochastic-growth methodology. The polymerized-actin distribution displays three types of behavior: a) traveling…
It has been shown that electron transitions, as measured in a scanning tunnelling microscope (STM), are related to chemical interactions in a tunnelling barrier. Here, we show that the shape and apparent height of subatomic features in an…
The nucleus of the eukaryotic cell functions amidst active cytoskeletal filaments, but its response to the stresses carried by these filaments is largely unexplored. We report here the results of studies of the translational and rotational…
Biological activity gives rise to non-equilibrium fluctuations in the cytoplasm of cells; however, there are few methods to directly measure these fluctuations. Using a reconstituted actin cytoskeleton, we show that the bending dynamics of…
Functionality of living cells is inherently linked to subunits with dimensions on the nanoscale. In case of osteoblasts the cell surface plays a particularly important role for adhesion and spreading which are crucial properties with regard…
Many biological functions rely on the reshaping of cell membranes, in particular into nanotubes, which are covered in vivo by dynamic actin networks. Nanotubes are subject to thermal fluctuations, but the effect of these on cell functions…
Friction measurements in the range of several meters per second are still of great interests. With the atomic force microscopy (AFM), the oscilaltion situation of the quartz crystal resonators of 3MHz resonance frequency are studied. And…
Forces acting between an Atomic Force Microscope (AFM) tip and sample are three dimensional. Despite this, most AFM force measurements are confined to one or two dimensions. Extending AFM force measurements into three dimensions has…
Measurements with an atomic force microscope (AFM) offer a direct way to probe elastic properties of lipid bilayer membranes locally: provided the underlying stress-strain relation is known, material parameters such as surface tension or…