Biofilms have emergent properties: traits that appear only when a system of individual items interacts. It was this emergence that attracted School of Physics Associate Professor Peter Yunker to the microbial structures. Trained in soft matter physics — the study of materials that can be structurally altered — he is interested in understanding how the interactions between individual bacteria result in the higher-order structure of a biofilm

Recently, in his lab at the Georgia Institute of Technology, Yunker and his team created detailed topographical maps of the three-dimensional surface of a growing biofilm. These measurements allowed them to study how a biofilm’s shape emerges from millions of infinitesimal interactions among component bacteria and their environment. In 2024 in Nature Physics, they described the biophysical laws that control the complex aggregation of bacterial cells.

The work is important, Yunker said, not only because it can help explain the staggering diversity of one of the planet’s most common life forms, but also because it may evoke life’s first, hesitant steps toward multicellularity.