Asymmetric interactions between molecules may serve as a stabilizing factor for biological systems. A new model from researchers of the department Living Matter Physics at the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) reveals this regulatory role of non-reciprocity. The scientists aim to understand the physical principles based on which particles and molecules are able to form living beings and, eventually, organisms.
Most organizations, may it be a company, a society or a nation, function best when each member carries out their assigned role. Moreover, this efficiency often relies on spatial organization, which arose due to rules or emerged naturally via learning and self-organization. At the microscopic level, cells operate in a similar way, with different components handling specific tasks. The scientists from MPI-DS aimed to understand how complex biological structures are created in the first place. In their models, they investigate the basic ingredients which are required for the formation of ordered structures and which are only based on simple interactions between different components.
"In a passive system, random interactions between particles are balanced and lead to the formation of stable patterns," explains Laya Parkavousi, first author of the study. "However, if we add non-reciprocal interactions to the system, meaning that one particle is attracted by another, which in turn is repelled, we observe activity that can homogenize the mixture," she continues. In other words, non-reciprocal interactions, which were investigated also in previous studies, allow to control the state of the particle organization.
"By tuning the non-reciprocity, we enable the system to adapt different states," says Navdeep Rana, shared first author of the study. "These states can be so-called molecular condensates within a cell which are not separated by a membrane or also waves of travelling information that is used in cellular signaling pathways," he explains. The study thus offers a new route to understanding how complex patterns and structures emerge and how cellular functions can be maintained.
