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This Defense Intelligence Agency reference document, dated 7 January 2010 and prepared under the Acquisition Threat Support series, surveys biomaterials used in medicine. It covers biocompatibility, biosensor membranes, silicones, Teflon, biodegradable polymers, hydrogels, titanium, bioceramics, tissue constructs, cardiovascular stents, contact lenses, drug delivery and dialysis. It concludes that biomaterial performance underlies many medical devices, that the industry is slow to adopt new materials because of testing costs, and that innovation mainly involves new applications of established materials.
UNCLASSIFIED//l'ert ePP!e!AL "SI! 8Hl!V medical therapeutics and differs from standard drug therapy or permanent implants in that the culture becomes integrated within the patient, affording a potentially permanent and specific cure of the disease state. There are many approaches to tissue engineering, but all involve one or more of the following key ingredients: harvested cells, introduction of specialized signaling molecules, and three-dimensional matrices. The approach involves seeding highly porous biodegradable matrices (or scaffolds) in the shape of the desired bone or tissue, with cells and signaling molecules (for example, protein growth factors), then culturing and implanting the scaffolds into the defect to induce and direct the growth of new bone or tissue. The goal is for the cells to attach to the scaffold, multiply, differentiate (that is, transform from a nonspecific or primitive state into cells exhibiting the specific functions), and organize into normal, healthy tissue as the scaffold degrades. The signaling molecules can be adhered to the scaffold or incorporated directly into the scaffold material. Figure 19 illustrates the sequence of steps in this process. ) 30 matrix Culture Implant Figure 19. Scaffold-Guided Tissue Regeneration Healty bone Perhaps the biggest challenge for tissue engineering is how to ensure angiogenesis in a timely fashion within the scaffold construct; without a blood supply, cells will die, and mass infection will occur. In biology, "autologous" refers to cells, tissues, or even proteins that are reimplanted into the same individual they were taken from. Bone marrow, skin biopsy, cartilage, and bone can be used as autografts. In contrast, cells or tissues transplanted from a different individual are referred to as allogeneic, homologous, or an allograft. TISSUE SCAFFOLD BIOMATERIALS An intriguing idea in tissue engineering is the use of biodegradable polymers as a scaffold for growing tissues of a certain defined shape-for example, the cartilage of an ear pinna lost in an accident. 14 UNCLASSIFIED//FQR QFFI&I.•k U&&i Qtllwlf
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 32 pages are in the text index: search them above, or from the library's search.