As a case in point, the microfluidic chip experiments by Coyte, now a postdoc at Memorial Sloan Kettering Cancer Center in New York, and her colleagues illuminated how the flow of water and the number of bacteria present can constrain and reconfigure the growth of biofilms.
Those biophysical forces are like universal zoning rules for the biofilm cities: they govern how the inhabitants obtain food and building materials, how they can move and how they interact with one another.
Scientists now know that the tooth plaque Leeuwenhoek described was actually a biofilm, not a simple collection of individual bacteria. What makes a biofilm different from a mass of identical bacteria are the multitudes of interactions among the component microbes. Many of the interactions among the bacteria in biofilms are intensely competitive, both within a biofilm and between them. The microbes in a biofilm can also specialize at different tasks, depending on where in the biofilm they are located and their genetic background.
In the past five to 10 years, advances in microscale engineering and high-resolution microscopy have allowed scientists to measure physical forces acting on individual cells and replicate a range of environmental conditions in the lab that have enabled scientists to begin to track the formation of a biofilm, cell by cell.