The image, taken with a scanning electron microscope (SEM) in the Microscopy Suite at the Beckman Institute, represents the cross-section of a polynuclear microcapsule embedded in an epoxy resin. From more than 100 entries, the image was chosen as one of the top three first-place winners.
The microcapsule is an example of the self-regulating material that is the signature work of the AMS Group. In this case, the material can be used in dental restorations, such as dental fillings.
“Several years ago we were approached by the National Institutes of Health National Institute of Dental and Craniofacial Research (NIDCR) about developing novel dental materials drawing from our original work on self-healing polymers,” said Scott White, a professor of aerospace engineering and member of the AMS Group. “Through that initiative we made contact with a group at the University of Illinois at Chicago lead by Dr. Ana Bedran-Russo and began a long term collaboration on innovative dental resins that prolong the life of dental restorations.”
Bedran-Russo, from the College of Dentistry at the University of Illinois at Chicago, has worked on various natural extracts, such as grape seed extract and tannic acid, to enhance the binding between teeth and filling material in order to construct long-lasting composite dental fillings. In clinical settings, however, the natural materials can be problematic: Applying all the extract at once may limit the length of time that the binding will last, and the extracts can cause adverse chemical reactions with the binding material.
The ideal solution is to release the natural extracts into the binding slowly over time.
“We were looking for ways to develop sustained and controlled release of the bioactives we isolated from plants so we could accelerate clinical implementation,” Bedran-Russo said. So she reached out to White, seeking expertise in creating such a method. A NIDCR supplement allowed the creation of a collaborative team.
Working with White, Yourdkhani encapsulated the extracts in polymer microcapsules to protect them from the composite resin monomers. The capsule used in the award-winning image was about 200 microns in diameter, but the capsules can be as small as 3 to 5 microns, perfect for dental materials. A recent paper in Dental Materials outlines the process.
The shell of the capsules is a biodegradable and biocompatible polymer, which allows for the gradual degradation of the shell polymer and slow release of the bioactive extract. The polynuclear structure of the capsules allows for continuous release of the extracts as the capsules degrade from the outermost layers toward the inner layers.
“That material will work longer, for less cost, less loss of dental tooth structure, and fewer visits to the dentist,” Yourdkhani said.
The research is sponsored by the National Institutes of Health. Mina Rezaeian, a graphic designer, helped with the final design of the artwork.
This article is part of the Fall 2017 Synergy Issue, a publication of the Communications Office of the Beckman Institute.