Judith Su^∗, Xingyu Jiang^†, Roy Welsch^‡, George M. Whitesides^§, Peter T. C. So^¶

Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 87-104, 2007, DOI:10.3970/mcb.2007.004.087

Abstract Interactions between the cell and the extracellular matrix regulate a variety of cellular properties and functions, including cellular rheology. In the present study of cellular adhesion, area was controlled by confining NIH 3T3 fibroblast cells to circular micropatterned islands of defined size. The shear moduli of cells adhering to islands of well defined geometry, as measured by magnetic microrheometry, was found to have a significantly lower variance than those of cells allowed to spread on unpatterned surfaces. We observe that the area of cellular adhesion influences shear modulus. Rheological measurements further indicate that cellular shear modulus is a biphasic function… More >

E. Takai¹, R. Landesberg², R.W. Katz², C.T. Hung³, X.E Guo^1,4

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 1-12, 2006, DOI:10.3970/mcb.2006.003.001

Abstract Osteoblast interactions with extracellular matrix (ECM) proteins are known to influence many cell functions, which may ultimately affect osseointegration of implants with the host bone tissue. Some adhesion-mediated events include activation of focal adhesion kinase, and subsequent changes in the cytoskeleton and cell morphology, which may lead to changes in adhesion strength and cell responsiveness to mechanical stimuli. In this study we examined focal adhesion kinase activation (FAK), F-actin cytoskeleton reorganization, adhesion strength, and osteoblast responsiveness to fluid shear when adhered to type I collagen (ColI), glass, poly-L-lysine (PLL), fibronectin (FN), vitronectin (VN), and serum (FBS). In general, surfaces that… More >

S. Deguchi^1,2, T. Ohashi², M. Sato²

Molecular & Cellular Biomechanics, Vol.2, No.4, pp. 205-216, 2005, DOI:10.3970/mcb.2005.002.205

Abstract Intracellular stress transmission through subcellular structural components has been proposed to affect activation of localized mechano-sensing sites such as focal adhesions in adherent cells. Previous studies reported that physiological extracellular forces produced heterogeneous spatial distributions of cytoplasmic strain. However, mechanical signaling pathway involved in intracellular force transmission through basal actin stress fibers (SFs), a mechano-responsive cytoskeletal structure, remains elusive. In the present study, we investigated force balance within the basal SFs of cultured smooth muscle cells and endothelial cells by (i) removing the cell membrane and cytoplasmic constituents except for materials physically attaching to the substrate (i.e., SF--focal adhesion complexities)… More >

S. Deguchi^1,2, T. Ohashi², M. Sato²

Molecular & Cellular Biomechanics, Vol.2, No.3, pp. 125-134, 2005, DOI:10.3970/mcb.2005.002.125

Abstract Actin bundles in vascular endothelial cells (ECs) play a critical role in transmitting intracellular forces between separate focal adhesion sites. However, quantitative descriptions of tension level in single actin bundles in a physiological condition are still poorly studied. Here, we evaluated magnitude of preexisting tension in a single actin bundle of ECs on the basis of measurements of its preexisting stretching strain and tensile properties. Cultured ECs expressing fluorescently-labeled actin were treated with detergents to extract acin bundles. One end of an actin bundle was then dislodged from the substrate by using a microneedle, resulting in a shortening of the… More >