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Nanoparticles break up plaque and stop decay
Materials Today Volume 00, Number 00 September 2016
NEWS
News Nanoparticles break up plaque and stop decay Nanoparticles could help break up the plaque that leads to tooth decay and cavities, according to researchers from the University of Pennsylvania [Gao, et al., Biomaterials 101 (2016) 272]. Dental plaque – a biofilm – consist of clusters of bacterial cells embedded in a fortress-like polymeric matrix that sticks like glue to any surface and is extremely difficult to remove, as any trip to the dentist can testify. Regular antimicrobial treatments do not remove or penetrate plaque, which can also create acidic conditions that erode tooth enamel. Not only is dental decay unpleasant for the individual, treating it costs up to $40 billion a year in the US alone. Now Hyun (Michel) Koo and his colleagues have developed a novel strategy to control dental plaque that relies on a combination of catalytic nanoparticles (or CATNP) made from biocompatible iron oxide (Fe3O4) and hydrogen peroxide (H2O2). ‘‘We used catalytic nanoparticles to activate a commonly used antiseptic agent, H2O2, to create a potent approach that dismantle the protective matrix and at the same time kill the embedded bacteria with exceptional efficacy,’’ explains Koo.
The nanoparticles catalyze the generation of free radicals, which simultaneously degrade the matrix and kill one of the strains of bacteria involved in tooth decay, Streptococcus mutans. The result is an exceptionally strong biocidal effect on S. mutans – killing over 99.9% of bacterial in less than 5 minutes–even at much lower concentrations of H2O2 than typical in clinical use. A treatment based on twice-daily topical application of CAT-NP followed by exposure to H2O2 suppresses the onset of dental decay without adversely affecting normal surrounding tissue, the researchers show. Nor did they find any evidence of harmful
effects on soft tissue in the mouth, such as inflammation or necrosis, in animal tests with rats. One of the reasons the treatment is so effective is that the nanoparticles bind to and are retained by the plaques. The nanoparticles also have an additional benefit of reducing demineralization, which the researchers believe is the result of trace amounts of Fe leaching from the particles. Under acidic conditions, the Fe ions could be incorporated into tooth enamel, forming a barrier of ferric phosphate that may disrupt the demineralization process. The researchers suggest that toothpastes or mouth rinses could be based on the strategy with the two components mixing together just before brushing or rinsing. The simplicity and success of the approach could have a broader reaching impact than just tooth decay because plaque is associated with several oral infections. ‘‘The main advantage is that our system has a multi-pronged effect,’’ says Koo. ‘‘It may provide a comprehensive strategy for biofilm disruption and cavity prevention.’’ Cordelia Sealy
1369-7021/http://dx.doi.org/10.1016/j.mattod.2016.09.005
1 Please cite this article in press as: C. Sealy, Mater. Today (2016), http://dx.doi.org/10.1016/j.mattod.2016.09.005
NEWS
News Nanoparticles break up plaque and stop decay Nanoparticles could help break up the plaque that leads to tooth decay and cavities, according to researchers from the University of Pennsylvania [Gao, et al., Biomaterials 101 (2016) 272]. Dental plaque – a biofilm – consist of clusters of bacterial cells embedded in a fortress-like polymeric matrix that sticks like glue to any surface and is extremely difficult to remove, as any trip to the dentist can testify. Regular antimicrobial treatments do not remove or penetrate plaque, which can also create acidic conditions that erode tooth enamel. Not only is dental decay unpleasant for the individual, treating it costs up to $40 billion a year in the US alone. Now Hyun (Michel) Koo and his colleagues have developed a novel strategy to control dental plaque that relies on a combination of catalytic nanoparticles (or CATNP) made from biocompatible iron oxide (Fe3O4) and hydrogen peroxide (H2O2). ‘‘We used catalytic nanoparticles to activate a commonly used antiseptic agent, H2O2, to create a potent approach that dismantle the protective matrix and at the same time kill the embedded bacteria with exceptional efficacy,’’ explains Koo.
The nanoparticles catalyze the generation of free radicals, which simultaneously degrade the matrix and kill one of the strains of bacteria involved in tooth decay, Streptococcus mutans. The result is an exceptionally strong biocidal effect on S. mutans – killing over 99.9% of bacterial in less than 5 minutes–even at much lower concentrations of H2O2 than typical in clinical use. A treatment based on twice-daily topical application of CAT-NP followed by exposure to H2O2 suppresses the onset of dental decay without adversely affecting normal surrounding tissue, the researchers show. Nor did they find any evidence of harmful
effects on soft tissue in the mouth, such as inflammation or necrosis, in animal tests with rats. One of the reasons the treatment is so effective is that the nanoparticles bind to and are retained by the plaques. The nanoparticles also have an additional benefit of reducing demineralization, which the researchers believe is the result of trace amounts of Fe leaching from the particles. Under acidic conditions, the Fe ions could be incorporated into tooth enamel, forming a barrier of ferric phosphate that may disrupt the demineralization process. The researchers suggest that toothpastes or mouth rinses could be based on the strategy with the two components mixing together just before brushing or rinsing. The simplicity and success of the approach could have a broader reaching impact than just tooth decay because plaque is associated with several oral infections. ‘‘The main advantage is that our system has a multi-pronged effect,’’ says Koo. ‘‘It may provide a comprehensive strategy for biofilm disruption and cavity prevention.’’ Cordelia Sealy
1369-7021/http://dx.doi.org/10.1016/j.mattod.2016.09.005
1 Please cite this article in press as: C. Sealy, Mater. Today (2016), http://dx.doi.org/10.1016/j.mattod.2016.09.005