Biological Active Matter
"Life is not in equilibrium" - this simple statement shows a gap in our physical understanding of the world. Living matter, such as motile bacterial colonies, developing embryos, and growing plants, does not fulfill the criterion of equilibrium as it is out of equilibrium. Particularly for living matter, this drive out of equilibrium stems from the material itself: Cells move and pull, and they grow and divide, leading to novel "living" terms in the classical description.
Self-propulsion breaks equilibrium by locally generating forces, driving the swimmer. It is important that the drive is coupled to the particle and not an external field. Thus a swimming sperm cell is a microswimmer, a sedimenting polymer is not. Sometimes, the activity due to swimming can be mapped to an elevated effective temperature, but more often than not, the activity manifests itself in phenomena inexplicable in equilibrium physics. Often, however, equilibrium concepts and analogies can be used to depict what is going on. For example, collections of self-propelled disks spontaneously "phase separate", motile tissues undergo "glass-like arrest" as density or adhesion increases, or non-equilibrium surface accumulation occurs. The Biological Active Matter group studies microswimmers in many different forms, ranging from generic self-propelled particles and filaments to hydrodynamic simulations of sperm and ciliated microswimmers.
While other forms of growing materials exist (like bacterial colonies or possibly polymers during polymerization), the prime example is biological tissues. Biological tissues form functional parts of organisms composed of cells. They develop during embryogenesis and (most) are under constant renewal over the course of their lifetime. In the past decades, it became more and more clear that physics, and especially mechanics, plays an important role in cellular and tissue growth. The group focuses on particle-based mesoscopic simulations of growing tissues, and on finite-element simulations to model cortical folding due to an imbalance of growth.
PD Dr. Jens Elgeti
Building 04.16 / Room 2006
Methods and infrastructures used
Mesoscopic Minimal Models, Computer simulations, high-performance computing, hydrodynamics, JURECA
- Microfold: Commercialization project to create microstructured surfaces, funded by Sprin-D and Innovation fund
- Sperm: A project within the ETN-PHYMOT Consortium “Physics of Microbial Motility” funded by the European Commission. The main aim is to arrive at a detailed understanding of swimming responses of sperm cells.