Figure 5: Comparison of the Live(green)/Dead(red) fluorescent ratio of biofilm formed on ALI and LLI models. (n=6, mean ± SEM) ** P<0.01 (using unpaired t-tests).
Extracellular polymeric substances staining
Alcian blue was used to stain polysaccharides in EPS to provide semi-quantitative data for biofilm formed on both the ALI and LLI models. The RGB ratio obtained from bright-field images of the stained biofilms is depicted in Fig.6. As the media contains starch, a relatively low blue ratio (≈0.3) was detected in the control group (membrane only). The RGB ratio for biofilm samples is significantly higher than the control sample, indicating that the biofilm has formed on the membrane. However, no significant difference between the ALI and LLI was present, suggesting that the quantity of EPS produced by different biofilm models is similar.