A5012141730- Cellular Mechanics and Interactions
- 3D Printing in Biomedical Research
- Force Microscopy Techniques and Applications
- Microfluidic and Bio-sensing Technologies
- Cell Adhesion Molecules Research
- Respiratory Support and Mechanisms
- Collagen: Extraction and Characterization
- Blood properties and coagulation
- Skin and Cellular Biology Research
- Microtubule and mitosis dynamics
- Lipid Membrane Structure and Behavior
- Intensive Care Unit Cognitive Disorders
- Avian ecology and behavior
- Bone Tissue Engineering Materials
- Cell Image Analysis Techniques
- Cancer Cells and Metastasis
- Magnesium Alloys: Properties and Applications
- Airway Management and Intubation Techniques
- Spaceflight effects on biology
- Polysaccharides and Plant Cell Walls
- Muscle activation and electromyography studies
- Muscle Physiology and Disorders
- Animal Behavior and Reproduction
- Hydrogen Storage and Materials
- thermodynamics and calorimetric analyses
Friedrich-Alexander-Universität Erlangen-Nürnberg
2016-2025
Max Planck Institute for the Science of Light
2013
Max Planck Society
2013
Brown University
2009
Harvard University
1999-2008
Boston University
2008
University of British Columbia
2007
Johns Hopkins University
2006
Harvard University Press
1999-2004
Boston Children's Hospital
2003
We report a scaling law that governs both the elastic and frictional properties of wide variety living cell types, over range time scales under biological interventions. This identifies these cells as soft glassy materials existing close to glass transition, implies cytoskeletal proteins may regulate mechanical mainly by modulating effective noise temperature matrix. The practical implications are is an easily quantified measure ability cytoskeleton deform, flow, reorganize.
Adherent cells exert tractions on their surroundings. These can be measured by observing the displacements of beads embedded a flexible gel substrate which are cultured. This paper presents an exact solution to problem computing traction field from observed displacement field. The rests recasting relationship between and into Fourier space, where recovery is especially simple. We present two subcases solution, depending whether or not outside cell boundaries set zero. implementation...
Living cells are an active soft material with fascinating mechanical properties. Under loading, exhibit creep and stress relaxation behavior that follows a power-law response rather than classical exponential response. Such puts in the context of colloidal glasses other disordered metastable materials share same In cells, however, both exponent stiffness related to contractile prestress cytoskeleton. addition, made highly nonlinear stiffens fluidizes under stress. They show adaptive such as...
Significance We report nonlinear rheology experiments on collagen type I networks, which demonstrate a surprising concentration independence of the network stiffness in elastic regime. develop model that can account for this, as well classical observations an approximate exponential stress–strain relationship collagenous tissues, microscopic has been lacking. Our also demonstrates importance normal stresses controlling mechanics fiber networks.
Cell invasion through a dense three-dimensional (3D) matrix is believed to depend on the ability of cells generate traction forces. To quantify role cell tractions during in 3D, we present technique measure elastic strain energy stored due traction-induced deformations. The deformations around were measured by tracking 3D positions fluorescent beads tightly embedded matrix. bead served as nodes for finite element tessellation. From each and known elasticity, computed local surrounding cell....
We show that the nonlinear mechanical response of networks formed from un-cross-linked fibrin or collagen type I continually changes in to repeated large-strain loading. demonstrate this dynamic evolution arises a shift characteristic stress-strain relationship higher strains. Therefore, imposed loading does not weaken underlying matrices but instead delays occurrence strain stiffening. Using confocal microscopy, we present direct evidence behavior results persistent lengthening individual...
Cell migration through connective tissue, or cell invasion, is a fundamental biomechanical process during metastasis formation. invasion usually requires adhesion to the extracellular matrix integrins. In some tumors, increased integrin expression associated with malignancy and Here, we have studied of cancer cells different α5β1 levels into loose dense 3D collagen fiber matrices. Using sorter, isolated from parental MDA-MB-231 breast two subcell lines expressing either high low amounts...
Abstract Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with dismal survival rate. Persistent activation of pancreatic stellate cells (PSCs) can perturb the biomechanical homoeostasis tumour microenvironment to favour cancer cell invasion. Here we report that ATRA, an active metabolite vitamin A, restores mechanical quiescence in PSCs via mechanism involving retinoic acid receptor beta (RAR-β)-dependent downregulation actomyosin (MLC-2) contractility. We show ATRA...
Mechanotransduction - how cells sense physical forces and translate them into biochemical biological responses is a vibrant rapidly-progressing field, important for broad range of phenomena. This forum explores the role mechanotransduction in variety cellular activities highlights intriguing questions that deserve further attention.
In dealing with systems as complex the cytoskeleton, we need organizing principles or, short of that, an empirical framework into which these fit. We report here unexpected invariants cytoskeletal behavior that comprise such framework. measured elastic and frictional moduli a variety cell types over wide range time scales using biological interventions. all instances stresses dominated at frequencies below 300 Hz, increased only weakly frequency, followed power law; no characteristic scale...
We describe a novel synchronous detection approach to map the transmission of mechanical stresses within cytoplasm an adherent cell. Using fluorescent protein-labeled mitochondria or cytoskeletal components as fiducial markers, we measured displacements and computed in cytoskeleton living cell plated on extracellular matrix molecules that arise response small, external localized oscillatory load applied transmembrane receptors apical surface. Induced displacements, stresses, phase lags were...
In patients mechanically ventilated for severe respiratory failure, system mechanics are non-linear, i.e., volume-dependent. We present a new computer-based multipoint method simultaneously determining volume-dependent dynamic compliance and resistance. Our is based on contin uously determined tracheal pressure (Ptrach). Tidal volume subdivided into six slices of equal size. One value (intrinsic PEEP considered) one resistance each slice by applying the least-squares-fit (LSF) analysis...
Quick release: The spatial and temporal delivery of active molecules (dyes or drugs) can be precisely controlled by the photocatalytic activity TiO2 nanotubes (see picture). cleavage link between molecule nanotubes, which are filled with magnetic Fe3O4 nanoparticles, occurs photoinduced chain scission under UV light; load released before photodegradation action photogenerated radicals occur. Detailed facts importance to specialist readers published as "Supporting Information". Such documents...
Intratracheal pressure (Ptrach) should be the basis for analysis of lung mechanics. If measured at all, Ptrach is usually assessed by introducing a catheter into trachea via lumen endotracheal tube (ETT). The authors propose computer-assisted method calculating on point-by-point subtracting flow-dependent drop delta PETT(V) across ETT from airway (P(aw)), continuously proximal end ETT.The pressure-flow relationship adult tubes with different diameters (ID, 7-9 mm) lengths and tracheostomy...
Living cells sense the rigidity of their environment and adapt activity to it. In particular, cultured on elastic substrates align shape traction forces along direction highest stiffness preferably migrate towards stiffer regions. Although numerous studies investigated role adhesion complexes in sensing, less is known about specific contribution acto-myosin based contractility. Here we used a custom-made single-cell technique measure force as well speed shortening isolated myoblasts...
Magnetic twisting cytometry probes mechanical properties of an adherent cell by applying a torque to magnetic bead that is tightly bound the surface. Here we have used three-dimensional finite element model deformation compute relationships between applied and resulting rotation lateral translation. From analysis, computed two coefficients allow elastic modulus be estimated from measurements either or translation, respectively, if degree embedding height are known. Although strains in...