A microfluidic platform for optical absorbance monitoring of bacterial biofilms

Through intercellular molecular signaling, many types of bacteria form biofilms, pathogenic matrices that characterize many clinical infections. A microfluidic platform for optical monitoring of biofilms was developed and tested. The platform was used to observe the dependence of Escherichia coli biofilm formation on bacterial signaling by monitoring the change in biofilm optical density over the growth period. After 60 hours of growth at 10 μL/hr, wild-type biofilms were approximately 275% more optically dense than biofilms formed by non-communicating bacteria. Communication was restored by extracellular addition of signaling molecules to non communicating bacteria. Results were corroborated by measurement of biofilm morphological properties via confocal microscopy. The presented platform presents the unique capability of continuous optical monitoring of unlabeled samples, and will be used to characterize biofilm formation and response in drug discovery applications.