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...

ABSTRACT In biological tissues such as bone, cell function and activity crucially depend on the physical properties of extracellular matrix which cells synthesize condition. During bone formation remodeling, osteoblasts get embedded into they deposit differentiate to osteocytes. These form a dense network throughout entire material. Osteocytes are known orchestrate remodeling. However, precise role osteocytes during mineral homeostasis their potential influence material quality remains...

Abstract Scaffolds for tissue engineering are usually designed to support cell viability with large adhesion surfaces and high permeability nutrients oxygen. Recent experiments the idea that, in addition surface roughness, elasticity chemistry, macroscopic geometry of substrate also contributes control kinetics deposition. In this study, a previously proposed model behavior osteoblasts on curved is used predict growth bone matrix pores different shapes. These predictions compared vitro...

Abstract White Blood Cell (WBC) Leukaemia is caused by excessive production of leukocytes in the bone marrow, and image-based detection malignant WBCs important for its detection. Convolutional Neural Networks (CNNs) present current state-of-the-art this type image classification, but their computational cost training deployment can be high. We here an improved hybrid approach efficient classification WBC Leukemia. first extract features from images using VGGNet, a powerful CNN architecture,...

This study investigated how substrate geometry influences in-vitro tissue formation at length scales much larger than a single cell. Two-millimetre thick hydroxyapatite plates containing circular pores and semi-circular channels of 0.5 mm radius, mimicking osteons hemi-osteons respectively, were incubated with MC3T3-E1 cells for 4 weeks. The amount shape the formed in pores, as measured using phase contrast microscopy, depended on geometry. It was further demonstrated, simple geometric...

The cytoskeletal protein vinculin contributes to the mechanical link of contractile actomyosin cytoskeleton extracellular matrix (ECM) through integrin receptors. In addition, modulates dynamics cell adhesions and is associated with decreased motility on two-dimensional ECM substrates. effect invasion dense three-dimensional gels unknown. Here, we report how expression affects into collagen matrices. Cell was investigated in knockout expressing wild-type mouse embryonic fibroblasts. Vinculin...

Magnetic micromanipulation using magnetic tweezers is a versatile biophysical technique and has been used for single-molecule unfolding, rheology measurements, studies of force-regulated processes in living cells. This article describes an inexpensive tweezer setup the application precisely controlled forces up to 100 nN onto 5 microm beads. High precision force achieved by parametric calibration method together with real-time control position current. are bead-magnet distances only few...

Vinculin binds to multiple focal adhesion and cytoskeletal proteins has been implicated in transmitting mechanical forces between the actin cytoskeleton integrins or cadherins. It remains unclear what extent mechano-coupling function of vinculin also involves signaling mechanisms. We report effect its head tail domains on force transfer across cell adhesions generation contractile forces. The creep modulus F9 mouse embryonic carcinoma cells (wild-type), knock-out (vinculin -/-), -/-...

The viscoelastic response of living cells to small external forces and deformations is characterized by a weak power law in time. elastic modulus the exponent with which stresses decay depend on active contractile prestress cytoskeleton. It unknown whether this also holds physiologically relevant regime large deformations. We used magnetic tweezers apply stepwise increasing beads bound cytoskeleton different cell lines, recorded resulting deformation (creep response). creep followed at all...

Osteocytes and their cell processes reside in a large, interconnected network of voids pervading the mineralized bone matrix most vertebrates. This osteocyte lacuno-canalicular (OLCN) is believed to play important roles mechanosensing, mineral homeostasis, for mechanical properties bone. While extracellular structure extensively studied on ultrastructural macroscopic scales, there lack quantitative knowledge how cellular organized. Using recently introduced imaging quantification approach,...

Fibroblasts transition into myofibroblasts in a highly tensed growth front and revert back to fibroblasts as the tissue matures.

The collective self-organization of cells into three-dimensional structures can give rise to emergent physical properties such as fluid behavior. Here, we demonstrate that tissues growing on curved surfaces develop shapes with outer boundaries constant mean curvature, similar the energy minimizing forms liquids wetting a surface. amount tissue formed depends shape substrate, more being deposited highly concave surfaces, indicating mechano-biological feedback mechanism. Inhibiting...

The light-promoted conversion of extensively used cyanine dyes to blue-shifted emissive products has been observed in various contexts. However, both the underlying mechanism and species involved this photoconversion reaction have remained elusive. Here we report that irradiation heptamethine cyanines provides pentamethine cyanines, which, turn, are photoconverted trimethine cyanines. We detail an examination substrate scope remarkable two-carbon phototruncation reaction. Supported by...

The ability of tumor cells to metastasize is associated with a poor prognosis for cancer. During the process metastasis, circulating in blood or lymph vessels can adhere to, and potentially transmigrate through, endothelium invade connective tissue. We studied effectiveness as barrier against invasion 51 cell lines into three-dimensional collagen matrix. Only nine showed attenuated presence an endothelial monolayer, whereas 17 became invasive significantly increased invasion. Endothelial...

Abstract Tumor cell invasion is the most critical step of metastasis. Determination mode within particular tumor for effective cancer treatment. Protease-independent amoeboid has been described in carcinoma cells and more recently sarcoma on treatment with protease inhibitors. To analyze invasive behavior, we compared highly metastatic parental nonmetastatic cells. The exhibited a functional up-regulation Rho/ROCK signaling and, similarly to cells, an invasion. Using confocal traction force...

Osteocytes interconnect with each other forming an intricate cell network within the mineralized bone matrix. One important function of osteocyte is mechano-regulation remodeling, where a possible mechanism includes fluid flow through porosity housing - lacuno-canalicular (OLCN). In our study OLCN in human osteons was three-dimensionally imaged aim to obtain quantitative description canalicular density and spatial variations this quantity osteons. The topology determined by first staining...

Abstract To survive antibiotics, bacteria use two different strategies: counteracting antibiotic effects by expression of resistance genes or evading their e.g. persisting inside host cells. Since bacterial adhesins provide access to the shielded, intracellular niche and adhesin type 1 fimbriae increases survival chances macrophages, we asked if also influenced evasion. Combined gentamicin assays, flow cytometry, single cell microscopy kinetic modeling dose response curves showed that...

Neurotransmitter release is stabilized by homeostatic plasticity. Presynaptic potentiation (PHP) operates on timescales ranging from minute- to life-long adaptations and likely involves reorganization of presynaptic active zones (AZs). At Drosophila melanogaster neuromuscular junctions, earlier work ascribed AZ enlargement incorporating more Bruchpilot (Brp) scaffold protein a role in PHP. We use localization microscopy (direct stochastic optical reconstruction [dSTORM]) hierarchical...

Adherent cells show a wide range of complex mechanical behavior that traditionally has been accounted for by different mechanisms and models, each which can explain limited subset cell behavior. Experimental evidence suggests nearly all aspects are closely associated with the cell's contractile machinery actin myosin filaments. We propose molecular details actin–myosin interactions be combined in unified active soft glassy model considers arrangement stress fibers at macro-scale, soft-glassy...

This paper reviews recent literature about the physical processes involved in cell interactions and tissue development. Rather than being exhaustive, we intend to provide illustrative examples of experiments theoretical approaches into how cells interact with other substrates form complex tissues organs. Forces geometry efficiently coordinate behaviour through feedback mechanical homeostasis, leading emergent properties not directly evident from individual cells. Two important for such are...

Background: Renal cell carcinoma (RCC) is divided into three major histopathologic groups—clear (ccRCC), papillary (pRCC) and chromophobe RCC (chRCC). We performed a comprehensive re-analysis of publicly available datasets from the TCGA (The Cancer Genome Atlas) database, thereby combining samples all subgroups, for an exploratory transcriptome profiling subgroups. Materials Methods: used FPKM (fragments per kilobase million) files derived ccRCC, pRCC chRCC cohorts representing...