Rheology of the Environment Regulates Bacterial Growth

Many bacterial communities inhabit complex environments such as soils and biopolymer gels secreted by a host or the bacteria themselves. In these settings, the cellular surroundings frequently have limited nutrient availability, are subjected to flow and mixing, and are rheologically complex. Within the human body alone, the rheological properties of a microbe's environment can change drastically depending on location in the body and host physiology. Here, by probing bacterial growth in hydrogel matrices with defined structural and rheological properties, we demonstrate that the rheology of the environment modulates flow-induced transport of essential nutrients—thereby regulating cellular physiology. Our work thus reveals a new mechanism, beyond mechanosensing, by which mechanics modulates microbial behavior.