Saturday, April 11, 2015

Plaque-busting nanoparticles could help fight tooth decay

Nanoparticles carry the antibacterial drug farnesol to the surface of the teeth, where they release their payload when triggered by acidic environments.

Nanotechnology might soon save you a trip to the dentist. Researchers have developed tiny sphere-shaped particles that ferry a payload of bacteria-slaying drugs to the surface of the teeth, where they fight plaque and tooth decay on the spot. The approach could also be adapted to combat other plaquelike substances, known as biofilms, such as those that form on medical devices like orthopedic implants.
"It's quite clever," says oral microbiologist Robert Allaker of Queen Mary University of London, who was not involved with the research. "I think it was an innovative piece of work."
Plaque is a film made up of bacteria and a matrix of polymers composed of linked sugars, which clings tenaciously to teeth. When bacteria digest sugars in the mouth, they produce acid as a byproduct, which eats away at teeth, eventually causing decay. Topical antibacterial drugs don’t work well on plaque because saliva quickly washes them away.

Nanoparticles can solve this problem by clinging to the surface of teeth and carrying drugs along with them. Although this is not the first technique to employ such a strategy, the research improves upon previous methods, because these particles attach not only to the tooth, but also to the plaque biofilm.

Friday, April 10, 2015

Engineers now understand how complex carbon nanostructures form

CNTs are much smaller than the width of a human hair and naturally form "forests" when they are created in large numbers. These forests, held together by a nanoscale adhesive force known as the van der Waals force, are categorized based on their rigidity or how they are aligned. For example, if CNTs are dense and well aligned, the material tends to be more rigid and can be useful for electrical and mechanical applications. If CNTs are disorganized, they tend to be softer and have entirely different sets of properties.

"Scientists are still learning how carbon nanotube arrays form," said Matt Maschmann, assistant professor of mechanical and aerospace engineering in the College of Engineering at MU. "As they grow in relatively dense populations, mechanical forces combine them into vertically oriented assemblies known as forests or arrays. The complex structures they form help dictate the properties the CNT forests possess. We're working to identify the mechanisms behind how those forests form, how to control their formation and thus dictate future uses for CNTs."
Currently, most models that examine CNT forests analyze what happens when you compress them or test their thermal or conductivity properties after they've formed. However, these models do not take into account the process by which that particular forest was created and struggle to capture realistic CNT forest structure.