Psl is one of the main exopolysaccharides secreted by Pseudomonas aeruginosa.Due to its very important role in biofilm development,finding new ways to regulate Psl then becomes a promising strategy for biofilm control.In this talk,I will discuss our recent work toward this direction,which focus on the role of Psl in bacterial surface motility using a parallel high throughput bacterial tracking technique.In the first half,I will show how bacteria respond to surfaces with different physiochemical properties by a comprehensive quantitative characterization of bacterial surface motility.The results implied an overshadow effect of Psl for cells to respond to different surfaces,as more Psl would weaken the influence caused by different physicochemical properties of surfaces.In the second half,I will show that by degrading Psl using a glycosyl hydrolase PslG,cell-surface adhesion and bacteria surface exploration pattern were altered and thus biofilm formation could be greatly retarded.Our results provide a PslG-based method to control biofilms through Psl-PslG interactions.