Streptococcus mutans is a pre-dominant bacterial species found in oral biofilms and participates in the production of dental caries via the generation of organic acids. The production of these acids results from the fermentation of carbohydrates present in a sugar-laden diet. As the acidity of an oral biofilm decreases, the demineralisation of the enamel of a tooth increases; leading to the formation of dental caries. To detect and measure the pH change occurring following a sugar challenge, ratiometric, fluorescent, pH-sensitive nanosensors were incorporated into oral biofilms. Confocal laser scanning microscopy revealed that the addition of glucose (1 % w/v) to an S. mutans biofilm resulted in a gradual reduction in the fluorescence intensity ratio during a 30 min period. This reduction in the fluorescence intensity ratio indicated a reduction in pH of the biofilm over time as the glucose was being fermented, resulting in the production and secretion of acids into the extracellular matrix of the biofilm. Additionally, a reduction in pH was detected – using widefield microscopy – in starved, planktonic S. mutans when treated with glucose. Over the course of 30 min, the pH of the medium was reduced from pH 5.3 to pH 3.3 as the glucose was fermented by the bacteria. These findings will help us map pH changes in oral biofilms as we examine potential methods of preventing the acidification of oral biofilms and the eventual demineralisation of the enamel; leading to the reduction in dental caries and an improvement in the standard of living of those effected.

  • This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error