On the role of the actin cytoskeleton and nucleus in the biomechanical response of spread cells.

Micropipette aspiration (MA) has been used extensively in biomechanical investigations of un-adhered cells suspended in media. In the current study, a custom MA system is developed to aspirate substrate adhered spread cells. Additionally, the system facilitates immuno-fluorescent staining of aspirated cells to investigate stress fibre redistribution and nucleus deformation during MA.

Influence of spreading and contractility on cell detachment.

Cell adhesion is a key phenomenon that affects fundamental cellular processes such as morphology, migration, and differentiation. In the current study, an active modelling framework incorporating actin cytoskeleton remodelling and contractility, combined with a cohesive zone model to simulate debonding at the cell-substrate interface, is implemented to investigate the increased resistance to detachment of highly spread chondrocytes from a substrate, as observed experimentally by Huang et al. (J.

Computational investigation of in situ chondrocyte deformation and actin cytoskeleton remodelling under physiological loading.

Previous experimental studies have determined local strain fields for both healthy and degenerate cartilage tissue during mechanical loading. However, the biomechanical response of chondrocytes in situ, in particular the response of the actin cytoskeleton to physiological loading conditions, is poorly understood. In the current study a three-dimensional (3-D) representative volume element (RVE) for cartilage tissue is created, comprising a chondrocyte surrounded by a pericellular matrix and embedded in an extracellular matrix.

The effect of remodelling and contractility of the actin cytoskeleton on the shear resistance of single cells: a computational and experimental investigation.

The biomechanisms that govern the response of chondrocytes to mechanical stimuli are poorly understood. In this study, a series of in vitro tests are performed, in which single chondrocytes are subjected to shear deformation by a horizontally moving probe. Dramatically different probe force-indentation curves are obtained for untreated cells and for cells in which the actin cytoskeleton has been disrupted.

Biomechanics of single chondrocytes under direct shear.

Articular chondrocytes experience a variety of mechanical stimuli during daily activity. One such stimulus, direct shear, is known to affect chondrocyte homeostasis and induce catabolic or anabolic pathways. Understanding how single chondrocytes respond biomechanically and morphologically to various levels of applied shear is an important first step toward elucidating tissue level responses and disease etiology.