Modeling growth and quorum sensing in biofilms grown in microfluidic chambers.

Biofilms are highly organized structures coordinately formed by multiple species of bacteria. Quorum sensing (QS) is one cell-cell communication mechanism that is used by bacteria during biofilm formation. Biofilm formation is widely acknowledged to occur through a sequence of spatially and temporally regulated colonization events. While several mathematical models exist for describing biofilm development, these have been developed for open systems and are not applicable to closed systems where biofilm development and hydrodynamics are interlinked. Here, we report the development of a mathematical model describing QS and biofilm formation in a closed system such as a microfluidic channel. The model takes into account the effect of the external environment viz the mass and momentum transport in the microfluidic channel on QS and biofilm development. Model predictions of biofilm thickness were verified experimentally by developing Pseudomonas aeruginosa PA14 biofilms in microfluidic chambers and reflect the interplay between the dynamics of biofilm community development, mass transport, and hydrodynamics. Our QS model is expected to guide the design of experiments in closed systems to address spatio-temporal aspects of QS in biofilm development and can lead to novel approaches for controlling biofilm formation through disruption of QS spatio-temporal dynamics.