JCo1: Targeted radical delivery for biofilm destruction via an electrocatalytic ceramic probe
PRESENTER: John S. Colombo, Ph.D.
AUTHORS: Ghazal Resael, Haley Whalen, Ogechi Amad, Robert Gherman, Krista Carlson, John S. Colombo
Introduction: In the oral cavity, populations of microbes are responsible for a number of prevalent diseases including periodontitis and pulpitis. Microbes assemble into complex, multi-organism biofilms, increasing their virulence and resistance to removal and treatment. Currently, the most effective way to remove biofilms is through mechanical disruption, although this is not always possible in difficult to access areas such as the dental pulp or in the periodontal space. Here we have adapted technology currently used to remove microbial populations in water systems; by passing low voltages current through titanium electrodes coated with anodically grown TiO2 microtubules, free oxide radicals can be generated. Before this technology can be adapted for use in the oral cavity, it must be shown that it is both safe for resident cell populations and effective at disrupting mixed oral biofilms.
Methods: Both clonally isolated rat dental pulp progenitor cells (DPPCs) and mixed salivary biofilms were exposed to free oxide radicals by passing 6V current through titanium electrodes for 0, 15, 100 and 300 seconds. Apoptosis, necrosis and cell viability proportions in the total population of DPPCs at each exposure time point were assessed by flow cytometry on an Attune NxT Flow Cytometer (ThermoFisher) through the use of the Apoptosis/Necrosis Assay kit (Abcam). Bacterial biofilms were stained with DAPI in order to visualize cell number and distribution.
Results: DPPCs exposed to oxide radicals showed no significant increases in apoptosis, necrosis or significant declines in viability at any exposure time point. Bacterial biofilms that were exposed to 100 and 300 seconds showed a reduction in visible cell number and a reduction in the density of cell distribution, suggesting biofilm disruption.
Conclusions: Titanium electrolytic generated free oxide radicals demonstrated the capacity to disrupt mixed salivary microbial biofilms at exposure levels that did have deleterious effects on DPPCs, indicating that this technology has potential utility in a number of dental applications.