[Characterization of the physical properties of biofilms]

It was known that bacteria adhere to surfaces and form sessile colonies called biofilms. Biofilms show potential applications for biodegradation and biocatalysis, whilst they also cause healthy and environmental problems. In particular, they lead to human infections and biofouling problems in industry. Physical properties of biofilms reflect the architecture and mechanical stability of biofilms that are highly related to their resistance to environmental challenges and their survival. In this article, we reviewed the physical properties involved in the development of biofilms and the related characterization techniques. The surface adhesion of bacteria plays a crucial role in the biofilm formation, which is determined by the motion of bacteria near a surface as well as the interaction between the bacteria and the surface. As far as the biofilms become mature, they behave like a polymer glassy material revealed by rheological measurements.