Functional channels in matureE. colicolonies

Abstract

17Biofilms are important in medicine, industry and the natural environment, however their structure 18 is largely unexplored across multiple spatial scales. We have studied the architecture of mature 19Escherichia coli macro-colony biofilms by means of the Mesolens, an optical system which 20 uniquely allows simultaneous imaging of individual bacteria and over one hundred cubic 21 millimetres of its biofilm milieu. Our chief finding is the presence of intra-colony channels on the 22 order of 10 µm in diameter in E. coli biofilms. These channels have a characteristic structure and 23 reform after total mechanical disaggregation of the colony. We present evidence that the channels 24 transport particles and function to assist the absorption of nutrients. These channels potentially 25 offer a new route for the delivery of dispersal agents or antimicrobial drugs to biofilms, ultimately 26 lowering their impact on public health and industry. 27