Environmental factors that affect Streptococcus mutans biofilm formation in a microfluidic device mimicking teeth

Streptococcus mutans is the primary etiological agent responsible for dental caries. Microfluidic devices have been used to provide a level of control over bacterial microenvironments under laminar flow conditions. In this study, we used a microfluidic device packed with glass beads to simulate the interproximal space, which is the space between the teeth. In the device, the effects of environmental factors, such as sucrose and metal ions, on S. mutans attachment and biofilm formation were quantitatively measured using confocal laser scanning microscopy and atomic force microscopy. We determined that sucrose was required for both bacterial attachment and exopolysaccharide (EPS) production in S. mutans. These results suggest that the in vivo condition between the teeth was successfully mimicked and that the device is highly suitable for in situ monitoring of oral biofilms.