3. Movement of Bacteria Towards Material Surfaces

Bacteria in planktonic states tend to move towards material surfaces. The main reason or driving force for the natural motion should be attributed to chemotaxis, where bacteria move in the direction of high-density nutrition. Carbon compounds adsorb on material surfaces and exist there generally as a very thin film. They attract planktonic bacteria in oligotrophic environments. However, various other factors would affect the bacterial movement in the vicinity of material surfaces. Flow is one of them. It could help bacteria and nutrients approach the material’s surface and also produce shear stress to make the biofilm stable, stronger, and thinner. The geographical configuration of a material’s surface is also a very important factor. In addition to them, chemical structures and properties (hydrophobicity–hydrophilicity, surface tension, and energy), the components of interfaces, etc. would affect the movement of bacteria in the vicinity of surfaces. In this chapter, those factors are explained and discussed.