Wendong Shi^∗,†, Xi-Qiao Feng^*, Huajian Gao^†

Molecular & Cellular Biomechanics, Vol.3, No.3, pp. 121-126, 2006, DOI:10.3970/mcb.2006.003.121

Abstract When pulling a vesicle adhered on a substrate, both the force-displacement profile and the maximum force at pull-off are sensitively dependent upon the substrate shape. Here we consider the adhesion between a two-dimensional vesicle and a rigid substrate via long-range molecular interactions. For a given contact area, the theoretical pull-off force of the vesicle is obtained by multiplying the theoretical strength of adhesion and the contact area. It is shown that one may design an optimal substrate shape to achieve the theoretical pull-off force. More >

Baohua Ji^*, Yonggang Huang^†

Molecular & Cellular Biomechanics, Vol.3, No.3, pp. 109-120, 2006, DOI:10.3970/mcb.2006.003.109

Abstract The mechanisms governing the self-assembled structure of biomolecules (single chain and bundle of chains) are studied with an AB copolymer model via the coarse grained molecular dynamics simulations. Non-local hydrophobic interaction is found to play a critical role in the pattern formation of the assembled structure of polymer chains. We show that the polymer structure could be controlled by adjusting the balance between local (short range) and non-local (long range) hydrophobic interaction which are influenced by various factors such as the sequences, chain length, stiffness, confinement, and the topology of polymers. In addition, the competition More >

X. Edward Guo^∗,†,‡, Erica Takai^∗,‡, Xingyu Jiang^§, Qiaobing Xu^§, George M. Whitesides^§, James T. Yardley^¶, Clark T. Hung^*, Eugene M. Chow^||, Thomas Hantschel^∗∗, Kevin D. Costa^∗

Molecular & Cellular Biomechanics, Vol.3, No.3, pp. 95-108, 2006, DOI:10.3970/mcb.2006.003.095

Abstract In this study, bone cells were successfully cultured into a micropatterned network with dimensions close to that of in vivo osteocyte networks using microcontact printing and self-assembled monolyers (SAMs). The optimal geometric parameters for the formation of these networks were determined in terms of circle diameters and line widths. Bone cells patterned in these networks were also able to form gap junctions with each other, shown by immunofluorescent staining for the gap junction protein connexin 43, as well as the transfer of gap-junction permeable calcein-AM dye. We have demonstrated for the first time, that the intracellular More >

Yong Gan^*, Zhen Chen^∗,†

Molecular & Cellular Biomechanics, Vol.3, No.3, pp. 89-94, 2006, DOI:10.3970/mcb.2006.003.089

Abstract Due to their nanoscale size and special features, carbon nanotubes could enter the human body via certain way. The growing use of carbon nanotubes in practical applications, hence, prompts a necessity to study the potential health risks of carbon nanotubes. A numerical study is performed in this paper to investigate the size effect of carbon nanotubes on the bulk modulus of a lipid bilayer by using the constant surface tension molecular dynamics simulation procedure. It is found that the size effect is not monotonic with the increase of nanotube length. An explanation is given on More >

Meghan H. Hoskins^*, Cheng Dong^∗,†

Molecular & Cellular Biomechanics, Vol.3, No.2, pp. 79-88, 2006, DOI:10.3970/mcb.2006.003.079

Abstract It has been determined previously that polymorphonuclear leukocytes, or PMNs, can facilitate melanoma cell extravasation through the endothelium under shear conditions [1,2]. The interactions between melanoma cells and PMNs are mediated by the β₂-integrins expressed by PMNs and intercellular adhesion molecules (ICAM-1) expressed on melanoma cells. In this study, the kinetics of these interactions was studied using a parallel plate flow chamber. The dissociation rates were calculated under low force conditions for ICAM-1 interactions with both β₂-integrins, LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18), together and separately by using functional blocking antibodies on PMNs. The kinetics of PMNs More >

Jui-Ming Yang^*, Philip R. LeDuc^∗,†

Molecular & Cellular Biomechanics, Vol.3, No.2, pp. 69-78, 2006, DOI:10.3970/mcb.2006.003.069

Abstract Inorganic and organic integrated systems detect, process, and respond to signals from solid media. Advances in fluidic systems have offered an alternative to traditional signaling methods through the development of aqueous signaling systems. Here, we show an experimentally simple mechanically governed fluidic system that creates three-dimensional molecular multiphase separation in a combination of discrete and continuous gradients analogous to digital and analog signals that can be used for controlled spatiotemporal cellular stimulation. We accomplish the pattern formation by fabricating a compartmentalized multi-level fluidics device where a network of capillaries converges into a main channel. Simultaneous More >

Guanbin Song^∗,†, Toshiro Ohashi^†, Naoya Sakamoto^†, Masaaki Sato^†

Molecular & Cellular Biomechanics, Vol.3, No.2, pp. 61-68, 2006, DOI:10.3970/mcb.2006.003.061

Abstract Expression of adhesion molecules may play an important role in the interaction of tumor cells with vascular endothelial cells during tumor invasion and metastasis. In this study, the adhesive force of human hepatoma HepG2 cells to human umbilical vein endothelial cells (HUVECs) was investigated using a micropipette aspiration technique. Expression of an adhesion molecule, E-selectin, was also observed by immunofluorescence microscopy. In particular, the adhesive force after stimulation of HUVECs with recombinant human interleukin-1β (rhIL-1β) was examined. The results demonstrated that the adhesive force of HepG2 cells to stimulated HUVECs is significantly higher than that More >

Shaohua Hu^*, Ning Wang^†

Molecular & Cellular Biomechanics, Vol.3, No.2, pp. 49-60, 2006, DOI:10.3970/mcb.2006.003.049

Abstract One fundamental question in cell biology is how mechanical stresses are distributed inside the cytoplasm. Recently we have developed a synchronous detection approach to map cytoplasmic displacements and stresses using yellow fluorescent protein tagged mitochondria as fiducial markers of the cytoskeleton (CSK) in response to a localized load applied via an RGD-coated magnetic bead (7). We have shown that stresses are propagated to remote sites in the cytoplasm, a finding that contradicts continuum model predictions. Here we show that long distance force propagation in the cytoplasm was abolished when the contractile prestress in the CSK More >

Konstantinos A. Lazopoulos¹, Dimitrije Stamenović²

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 43-48, 2006, DOI:10.3970/mcb.2006.003.043

Abstract It is well documented that in response to substrate stretching adhering cells alter their orientation. Generally, the cells reorient away from the direction of the maximum substrate strain, depending upon the magnitude of the substrate strain and the state of cell contractility. Theoretical models from the literature can describe only some aspects of this phenomenon. In the present study, we developed a more comprehensive mathematical model of cell reorientation than the current models. Using the framework of theory of non-linear elasticity, we found that the problem of cell reorientation was a stability problem, with the More >

K.Y. Volokh¹

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 35-42, 2006, DOI:10.3970/mcb.2006.003.035

Abstract It is common practice in the arterial wall modeling to assume material incompressibility. This assumption is driven by the observation of the global volume preservation of the artery specimens in some mechanical loading experiments. The global volume preservation, however, does not necessarily imply the local volume preservation -- incompressibility. In this work, we suggest to use the arterial ring- cutting experiments for the assessment of the local incompressibility assumption. The idea is to track the local stretches of the marked segments of the arterial ring after the stress-relieving cut. In the particular case of the rabbit… More >