The extracellular matrix in which biofilm cells are embedded plays significant structural and functional roles for biofilm biology and ecology. The biofilm matrix is a fundamental component of biofilms. It is comprised of a mixture of extracellular polymeric substances (EPS), such as proteins, lipids and nucleic acids, which provides skeletal support for member microbes. The matrix functions as an active part of a biofilm, where it acts as an electroconductive medium, as well as serving as a reservoir for nutrients, exoenzymes, siderophores and signaling molecules. The sequestration of such enzymes and bioactive molecules can facilitate extracellular digestion and capture of nutrients, as well as processes such as quorum sensing within the biofilm community.
Despite this integral role, the matrix is a relatively understudied component of the biofilm, classically limited to chemical extraction of extracellular polymeric substances (EPS). Understanding biofilms in their entirety requires a sound knowledge of both the biological cells and the extracellular matrix environment. Given that the matrix properties may change as different EPS components are produced, the matrix composition may have a significant impact on the physiology of the enmeshed cells. Studies of the matrix, its components and properties as well as their impact on the underlying cells require a strong interdisciplinary platform.
SCELSE utilises several biophysical approaches, which allow for quantification of biofilm structure/function in ways classical microbiological approaches cannot. Some of these include:
- Biofilm rheology and viscoelasticity at different stages of development, and at different loci in the biofilm, and the contribution to these characteristics by specific matrix components [link to Chew et al. 2014];
- Matrix diffusivity, its heterogeneity, and dynamics of change, with outcomes informing on for example the penetration by antimicrobials and the trafficking of signals in both population and mixed species communities [link to Chiang et al. 2013];
- Establishing the role of structural molecules such as filamentous phage, eDNA, amyloids and novel nanowires, as well as well as soluble signaling compounds and electron shuttles; of matrix components which have only recently been identified (Ng et al. 2013a, Seviour et al. 2012); and
- Establishing the role of matrix electroconductivity for co-metabolism, respiration, and energy as well as mediating microbial corrosion [links to Hinks et al. 2014, Wang et al. 2014, Wang et al. 2013(b), Wang et al. 2013 (c)].