(3eq) Investigating Biofilm-Material Interactions: From Biofouling to Bioremedation to Pathogenesis

Diagnostic measurements of biofilm-material interactions currently struggles to identify changes in biofilms beyond species presence and live/dead. However, most bacteria responsible for disease are intermittently pathogenic, which are controlled by distinct signals. In fact, many bacteria associated with pathogenesis exist in a non-pathogenic form in the natural human microbial flora. Current methods in evaluating bacterial biofilm pathogenicity are focused on evaluating overall biofilm presence and/or viability. This approach implements bulk evaluation that limits the ability discern if a live biofilm is exhibiting pathogenic properties, or is surviving in a non-pathogenic capacity.  In an attempt to evolve analytical techniques to distinguish living biofilms in pathogenic and non-pathogenic modes, acidogenic dental pathogen Streptococcus mutans was used as a model. In this study, sucrose was used to control the exhibition of S. mutans pathogenic properties, which were then evaluated by surface enhanced Raman spectroscopy (SERS) to identify unique chemical signatures and rheology to evaluate the mechanical properties of biofilms grown directly on the instrument in a specially designed bioreactor. These techniques require minimal sample preparation and offer a rapid, low-cost, high throughput system for clinical evaluations, or evaluating of the capacity of various materials to affect bacterial-mediated biofilm pathogenesis.

Evaluating the efficacy of dental materials to protect human teeth requires the capacity to measure tooth accurately and precisely decay. Current practices for determining tooth decay are destructive, qualitative to lowly quantitative, and/or measure bulk changes that have low to no spatial resolution. The combination of the highly variable nature of tooth enamel and the inability to perform serial analyses on the same spatial location limits the capacity to access reproducible information from any experimental set. This study explores the potential of interferometric optical profilometry to make rapid precision spatial measurements in 3-dimensions (3-D) over time (4-D) of human tooth enamel decay as a complementary measurement to existing techniques. In this study, using bioinert 3-D alignment translation stages, human tooth decay was measured with respect to pathogenic dental bacterial biofilms. These investigations demonstrate the ability to quantitatively determine the rate of tooth decay in previously unseen spatial and temporal scales. These new, rapid, low-cost techniques minimize effort for sample preparation and use very few consumables, opening the feasibility for high-throughput investigations of clinical dental materials to a wider international community.