One biological system that might be of key importance in future development of architecture is the bacterial biofilm. The term biofilm refers to complex heterogeneous structures comprising different populations of microorganisms that attach and form a community on an inert (e.g. rocks, glass, plastic) or organic (e.g. skin, cuticle, mucosa) surfaces. The properties of the surface, such as charge, hydrophobicity and roughness, determine initial bacterial attachment. A common principle of all biofilms is the production of extracellular matrix (ECM) composed of different organic substances, such as extracellular proteins, exopolysaccharides and nucleic acids. While the ability to generate ECM appears to be a common feature of multicellular bacterial communities, the means by which these matrices are constructed and function are diverse.