Out of Many, One: Modeling Schemes for Biopolymer and Biofibril Networks

Tissues are structurally and compositionally complex materials that must function in a coordinated fashion at multiple length scales. Many of the structural proteins in soft tissues and in cells form biopolymer networks that provide mechanical benefits and coordinate cell-directed physiological activities. Complicated phenomena operate at multiple scales and are governed to varying degrees by the properties of networks; thus, mechanical models are a necessary tool to unravel the relationships among individual network components and to determine the aggregate properties and functions of cells and tissues. In this work, we review major biopolymers, their function, and the general mechanical behavior of biopolymer gels. We then discuss some network imaging techniques and methods for constructing and modeling networks /in silico/– including multi-scale methods. Finally, we return to the specific biopolymers, including actin, microtubules, intermediate filaments, spectrin, collagen I and IV, laminin, fibronectin, and fibrin, and discuss what has been learned from the different models. Biopolymer network models, especially when combined with ever-improving experimental methods, have the potential to answer many fundamental questions in mechanobiology.