(535c) Real-Time Monitoring of Streptococcus Mutans Dental Biofilm Formation Using Quartz Crystal Microbalance

Streptococcus mutans is a known etiological agent in dental
caries (tooth decay) and metabolizes sugars to produce organic acids such as
lactic acid which contribute to the cariogenic process.  Its metabolism of
sucrose produces glucans, a ?sticky? substance that S. mutans uses to
secure and shelter its biofilm environment. Previous research has focused on
static measurements. We present real-time, non-invasive monitoring data of S.
mutans biofilm attachment using a quartz crystal microbalance (QCM) capable
of detecting mass accretion at the resolution of nanograms. QCM is a technology
which correlates the shift of resonant frequency of an AT-cut quartz crystal to
the change in mass that is attached onto the crystal surface and is usually
used for rigid films. Modifications to correlations of frequency change and
mass accumulation were determined for application of QCM to viscoelastic films
such as a biofilm.  Kinetic information on the growth of the biofilm as a
function of sucrose concentrations of 0, 0.01, 0.05, 0.1, 0.25, 0.5, and 1%
(v/v) were obtained for investigation of the biofilm attachment and growth dynamics.
In addition, QCM monitoring of various mutants of S. mutans with ciaH,
luxS, gtfB or gtfC genes removed which are responsible for
mutacin production, quorum sensing, or glucans production, were found to
significantly affect biofilm architecture and ability to generate stable
biofilms. Results of these experiments will be discussed. This project was
supported through a NIH grant.