biomechanics

Arteries are living organs that can remodel themself in response to stress changes. Arterial remodeling is a big topic and this paper shows only a tip of the iceberg.

A new book, "Tissue Mechanics" by SC Cowin and SB Doty is of potential interest to those from a classical mechanics background considering work in biomechanics. Downloadable versions of the first two chapters are available at the book's website along with a full table of contents and other supplemental information.

I am chairing the search for a new faculty member in the Materials Science and Engineering Department at Lehigh. As you will see in the ad below, the position is in the Biomaterials area. I would like to encourage more applications from candidates with interests in biomechanics (so I will have good opportunities to collaborate), and would like to invite applicants from this forum. If you are not personally in a position to apply, please pass the announcement along to anyone you know who might be suitable.

Abstract submission is now open for the 2007 ASME Summer Bioengineering Conference, 20-24 June, 2007 in Keystone, Colorado. Full details can be found on the conference website. Please note that there is a vibrant and competitive student paper competition for different

Robust biomechanical models are essential for studying the nuclear mechanics and can help shed light on the underlying mechanisms of stress transition in nuclear elements. Here, we develop a computational model for an isolated nucleus undergoing micropipette aspiration. Our model includes distinct components representing the nucleoplasm and the nuclear envelope. The nuclear envelope itself comprises three layers: inner and outer nuclear membranes and one thicker layer representing the nuclear lamina.

This is a paper by Jizhong Lou and myself, which is in press in Biophysical Journal.

Abstract.  Catch bonds, whose lifetimes are prolonged by force, have been observed in selectin-ligand interactions and other systems. Several biophysical models have been proposed to explain this counter-intuitive phenomenon, but none was based on the structure of the interacting molecules and the noncovalent interactions at the binding interface. Here we used molecular dynamics simulations to study changes in structure and atomic-level interactions during forced unbinding of P-selectin from P-selectin glycoprotein ligand-1. A mechanistic model for catch bonds was developed based on these observations. In the model, "catch" results from forced opening of an interdomain hinge that tilts the binding interface to allow two sides of the contact to slide against each other. Sliding promotes formation of new interactions and even rebinding to the original state, thereby slowing dissociation and prolonging bond lifetimes. Properties of this sliding-rebinding mechanism were explored using a pseudo-atom representation and Monte Carlo simulations. The model has been supported by its ability to fit experimental data and can be related to previously proposed two-pathway models.

We know - or believe - protein function is determined by structure. Crystallographic and NMR studies can provide protein structures with atomic-level details at equilibrium. MD simulations can follow protein conformational changes in time with fs temporal resolution in the absence or presence of a bias mechanism, e.g., applied force, used to induce such changes.