biofilm

noun

aggregation of microorganisms on a surface shielding them from harmful substances in the environment

Etymology: From bio- + film. First used in the early 1970s in the context of wastewater treatment.

A thin film of mucus created by and containing a colony of bacteria and other microorganisms.
“The differences in biofilm penetration patterns of both tested photosensitisers and the light source could have played an important role for the survival of microorganisms after the application of aPDT. In a recent own study, we showed that the deepest layers of the oral biofilm were not affected by the aPDT [4 ].”
“These interactions are essential for the assembly of an exopolysaccharides-rich matrix and the development of cospecies biofilms.”