Fig. 2. Analysis of 3-D bacteria-polysaccharides structure in mature biofilms of S. mutans strains.

a Biofilm architecture was observed by SEM, in which images were taken at 1 000×, 5 000×, and 20 000× magnifications, respectively (EPS: red arrows). b Representations of glucans distribution and biofilm reconstructions were revealed by CLSM, where EPS stained with Alexa Fluor 647 were red and total bacteria stained with SYTO9 were green. Images were taken at 20× magnification and the scale bar indicated 100 μm. Smu_vicK biofilms showed small clusters of bacterial cells without enough EPS filling the space between them (light blue arrows). c Quantification of EPS and bacteria components, as well as EPS/bacteria ratios at different heights were performed with COMSTAT