Multiscale simulation of soft tissue mechanobiology
In contrast to classical engineering materials, that typically seek to maintain or attain a relaxed, stress-free state, living tissues intend to establish and maintain a certain non-zero target stress, a behavior that is often referred to as tensional homeostasis. Moreover, living tissues respond to mechanical stimuli such as stress or strain by an accurately controlled process of growth and remodeling, a behavior that is often referred to as mechanobiology and that is intimately linked to a host of biochemical and biological processes. It plays key roles in numerous diseases as well as the long-term response of the human body to surgical interventions or implants and protheses. Nevertheless, its micromechanical and mathematical foundations remain poorly understood. Developing reliable mathematical and computational multiscale models based on a strong experimental foundation to understand and predict mechano-regulated growth and remodeling in soft tissues remains one of the most important challenges in biomechanics.
In collaboration with partners at Yale University we are currently studying in a custom-built biaxial bioreactor the micromechanical and mathematical foundations of soft tissue mechanobiology, considering in particular the underlying coupling between mechanical, biochemical and biological processes.
Based on data gained in these experiments, we developed a tailor-made and currently world-wide unique high-performance computational framework for simulating the micromechanical interaction of cells with individual polymer chains modeled as continua and discretized by finite elements (such as fibroblasts or smooth muscle cells). Using our discrete fiber network model, we are also capable of studying other key phenomena in medicine and biomedical engineering like three-dimensional cell migration.
Computer simulations on the microscale help to understand the microscopic foundations of mechanobiology (e.g. of tensional homeostasis) and formulate them in mathematical/mechanical laws that form the basis for computer simulations of the whole aneurysm on the macroscale. Within the field of macroscale modeling, we have recently introduced as a new approach so-called homogenized constrained mixture models allowing us to address in a conceptually simpler and computationally more efficient way the inelastic behavior of polymer materials that results in particular from biological growth and remodeling processes.
