[On the relationship between exopolysaccharides and Actinomyces viscosus in biofilms]

To elucidate the biofilm structure of Actinomyces viscosus and the spatial distribution of exopolysaccharides in it.

The Actinomyces viscosus biofilm was made by allowing bacteria to attach to the cover glass surface. The biofilm structure and exopolysaccharides distribution at 24 hours were stained with Fluorescein, BODIPY and Calcofluor respectively and were visualized by confocal laser scanning microscopy (CLSM).

Actinomyces viscosus could attach to glass surface and form a structural biofilm where bacteria were embedded in the EPS glycocalyx polymers, and characteristic microcolonies and channels were taking shape. Bacteria were sparse in the substratum area but crowd in the center. In the biofilm, the distribution of bacteria was consistent with the distribution of exopolysaccharides.

The findings demonstrate an important role of exopolysaccharides in the process of Actinomyces viscosus biofilm formation.