Researchers from the American Dental Association Foundation and the National Institute of Standards and Technology (NIST) have developed a new technology for implants that may improve construction or repair of bones in the face, skull, and jaw. The new technology provides a method for making scaffolds for bone tissue. The scaffold is seeded with a patient’s own cells and is formed with a cement paste made of minerals also found in natural bone. The paste is mixed with beads of a natural polymer (made from seaweed) filled with bone cells. The paste is shaped or injected into a bone cavity, then allowed to harden with the encapsulated cells dispersed throughout the structure. The natural polymer beads gradually dissolve when exposed to the body’s fluids, and this creates a scaffold that is filled by the now-released bone cells. Adding chitosana, a biopolymer extracted from crustacean shells, strengthens the cement, a calcium phosphate material. The implant is further reinforced to about the same strength as spongy natural bone by covering it with several layers of a biode-gradable fiber mesh already used in clinical practice. The researchers used mouse bone cells in their experiments, but in practice surgeons would use cells cultured from patient samples. In addition to creating pores in the hardened cement, the natural polymer beads protect the cells during the 30 minutes required for the cement to harden. Future experiments will develop methods for improving the material’s mechanical properties by using smaller encapsulating beads that biodegrade at a predictable rate.
(Source: NIST, Apr 15, 2006)
