Advances in cell biology and material science have led to the concept of repairing or regenerating lost or damaged tissue by providing healthy progenitor cells to the injured site on a biocompatible scaffold. The success of this most desirable treatment rests on the development of 3D structures to which cells can attach and form firm bonds. The ideal material to make such scaffolds should be biomechanically similar to the host tissue and must be biocompatible, preferably be bioactive so as to actively control tissue growth. The most successful results of this approach have been obtained for bone replacement using bone-scaffolds made from CaO-P2O5-SiO2 based glasses. A macro porous structure is necessary to obtain good implant incorporation through rapid vascularization and bone ingrowth, yet an ideal scaffold should consist of nanopores that simulate the extracellular environment for the development of connective tissue. Thus an ideal bone-scaffold must consist of a bimodal distribution of nano-macro pores. The process for fabricating bimodal porosity in a bioactive glass with prescribed mechanical and biocompatibility properties does not exist. Therefore, a comprehensive research program is proposed for fabricating bone-scaffolds and demonstrating their efficacy under controlled in vitro and realistic in vivo environment (alveolar bone regeneration utilizing bone marrow mesenchymal stem cells). Sol-gel method will be the primary method of glass preparation in which bimodal porosity will be introduced in established Bioglass type compositions either by polymerization-induced phase separation simultaneously with the sol-gel transition, or via macroporous templates. To optimize the glass composition and processing parameters, we will investigate the physical and chemical structure of the bulk and surface of glass, the bone-scaffold interface, and newly formed bone. The very broad scope of our goal will be pursued collaboratively by glass synthesis chemists, physical glass scientists, surface scientists, dentists with expertise in tissue engineering, and biomechanics specialists, forming a team of five groups from Egypt, Portugal, Senegal and USA.
With regard to broad impact, the project will help develop a better treatment of bone tissue loss in aging population or patients suffering from a trauma. Our novel bioactive nano-macro porous glass-scaffold would not only help orthopedic patients, but may also introduce new technology for drug delivery and cell encapsulation. It will demonstrate the benefits of materials science and engineering in advancing the cutting edge of medicine. It will also help establish a focused materials world network of researchers in cross-disciplinary materials research, and train young scientists in four countries from three continents with one common goal. The project will be creating the first comprehensive research programs of bioactive materials in two developing countries, and thus setting a model for future research in this area of research. The projects impact will be amplified via its alignment with NSFs two International Materials Institutes at Lehigh and Princeton Universities.
This award is co-funded by the Africa and Near East Programs of the NSF Office of International Science and Engineering.
