The Sfeir Laboratory currently has multiple ongoing research projects relating to the topics below:
Scaffolds for Tissue Engineering
- Resorbable Metals: Resorbable metals such as magnesium (Mg) and its alloys have several advantages over other orthopedic materials. For instance, Mg alloys have a fracture toughness greater than many ceramic materials, and a yield strength and stiffness more similar to cortical bone. Furthermore, Mg implants degrade naturally in vivo, reducing risk of long-term complications and eliminating the need for removal surgeries. When properly controlled, this degradation causes minimal inflammation, and may benefit the body as Mg is a natural component of bone and a co-factor for hundreds of enzymatic processes. For these reasons, we are exploring Mg alloys as bone fixation devices for orthopedic and craniofacial applications. Specifically, we are designing and testing Mg-based fixation devices to better understand their degradation and subsequent biological effect.
- Composites: Composite materials, such as Mg/PLGA have the potential to serve as fully degradable implants for guided bone regeneration (GBR). During GBR, bone graft material and membranes or meshes are implanted to promote bone regeneration for subsequent implant placement. Currently available reinforced membranes and meshes are typically non-degradable, forcing the surgeon to perform a second removal surgery following healing. To overcome this issue, we are developing a fully degradable alternative (PerioMag GBR), which includes a mechanically reinforced, yet fully degradable, barrier membrane comprised of a Mg mesh embedded in an FDA approved polymer (PLGA).
- Protein-based Polymer Gels: Biomimetic approaches inspired from the extracellular matrix (ECM) of bone and dentin are being used to design novel scaffolds for tissue regeneration. These scaffolds can be impregnated with genes and growth factors for controlled and sustained release of these agents into the developing tissue.
- Bone Putty: We have developed novel biocompatible nanoparticles of calcium phosphate that can be used as a non-viral method of delivering genes, such as those that regulate the formation of bone and teeth. Several forms of these nanoparticles have been synthesized successfully and tested for their ability to transfect cells.
Biominerals, such as those found in shells, bones, and teeth are produced by organisms ranging from bacteria to higher plants and mammals. Our studies are focused on understanding basic strategies of mineralization in biological systems and on applying those strategies to the design of new, nanostructured composite materials.
Cell Differentiation and Signaling
- Mineralized Structures: The ECM serves as an appropriate microenvironment or niche for cell differentiation by providing cues for activation of specific cell signaling pathways. Currently, we are investigating the role of the ECM of bone and dentin in cell signaling and differentiation. Specifically, we are identifying signaling pathways and regulation systems for expression of bone and dentin genes. Through an improved understanding of these pathways, we may guide cells to develop into specific tissues for regenerative therapies.
- Cell-surface Interactions: Studying how fabricated surface patterns affect stem cells illustrates the biology of cells as they interface with the next generation of tissue engineered scaffolds.
- Mg Signaling Pathways: Ongoing work from our laboratory has shown a positive effect of Mg on bone; however, the mechanism of this effect remains relatively unknown. For this reason, we are studying Mg specific signaling pathways which may play a role in bone formation. These investigations will allow us to tailor our Mg implants to exploit their positive effect on bone formation.
Material Synthesis / Rapid Prototyping / 3D Manufacturing
We are developing three dimensional scaffolds of single and composite materials. These scaffolds have the potential to generate the combination of soft and mineralized tissues necessary for the restoration of facial function.
Our research is focused on clinical applications across a broad range of fields including craniomaxillofacial surgery, orthopedics, dentistry, endodontics, and periodontics. This research will provide potential therapies for bone and dentin regeneration, craniosynostosis, periodontal regeneration, and cleft lip and palate. Furthermore, this work will soon make several landmark achievements possible, including the synthesis of materials based on bone/dentin proteins, the growth of teeth in vitro, the creation of novel biomaterials based on nanotechnology, and a suite of new mineralized tissues and structures.