Hyun Koo, D.D.S., Ph.D.

The role of extracellular polysaccharide matrix in the pathogenicity of oral biofilms; Development of effective therapeutics against biofilms

Research Overview

Oral diseases related to dental biofilms continue to afflict the majority of the World's population. Among them, dental caries is the most prevalent and costly oral infectious disease. This ubiquitous disease results from the interaction of specific bacteria and constituents of the diet within biofilms formed on the tooth surface. The majority of biofilm matrices are composed of polysaccharides, which provide bacterial binding sites, physical integrity and stability on the surface and influence the microenvironment of the biofilm. The exact structural and molecular basis of the role of these extracellular polysaccharides (EPS) in the development of cariogenic biofilms is being actively explored.

Our laboratory is focused on three major goals: 1) to understand the sequence of synthesis and assembly of complex polysaccharides (mostly high-molecular-weight polymers of glucose and fructose) in the matrix at molecular and structural levels using genomic, spectroscopic and fluorescence imaging techniques, 2) to elucidate how the structural and biophysical changes in the matrix affect the pathogenicity of the biofilms, and 3) to develop novel anti-biofilm therapies that could disrupt EPS matrix formation. We are particularly interested in finding new naturally occurring anti-biofilm agents from plant-derived foods and organic waste products. We work primarily with mono- and multi-species biofilms; Streptococcus mutans is our model organism because this bacterium is a key contributor for the synthesis of EPS and acid production within biofilms, and generally regarded as the primary microbial culprit of dental caries.

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