Influence of Medium Concentration, Surface Properties, and Chemotaxis on Biofilm Formation of Pseudomonas aeruginosa in Microfluidic Channels

Biofilms, groups of bacteria that adhere to wet surfaces and resist antibiotics, often cause chronic infections and complications with medical devices. Despite their critical role in various environments, a significant gap remains in understanding biofilm dynamics within common ecological settings. Here, we investigate the formation and development of biofilm streamers in microfluidic channels using Pseudomonas aeruginosa PAO1 and its chemotaxis-blind mutant PC4. We find that biofilm streamers consistently form at the corners of microfluidic channels under low-speed flow conditions. We observe that higher concentrations of LB medium lead to the development of mature biofilms, while lower concentrations favor the formation of streamers. Also, the surface properties of the microfluidic channels significantly influence biofilm formation. The PEL-coated surfaces are more favorable to form biofilm streamers compared to bare glass surfaces. Furthermore, we investigate the role of chemotaxis with wild-type PAO1 strains formed streamers differently compared to the PC4 mutant, which confirms that chemotaxis significantly impacts streamer formation. These findings offer valuable insights into the physical and biological factors affecting biofilm development in microfluidic environments and provide important information for further studies on bacterial biofilms.