ABSTRACT
The use of biomedical implants, commonplace in current surgical practice to replace and repair tissue functions, is increasing with the aging population (Gunterberg et al. 1998; Branemark et al. 2001). Despite signi cant contributions to quality of life, patient functional restoration, and generally acceptable safety records, implanted materials in many situations are notoriously plagued by insult from the host immune system and subsequent unresolved consequences of host in§ammation. The formalized concept of implant “biocompatibility”—the ability of a material to perform with an appropriate host response in a speci c application (Williams 1987, 1999)—is perhaps more accurately described functionally by the more lenient term “biotolerability,” where implant healing responses within host tissues remain abnormal and unresolved, without compromising implant function suf ciently enough to require removal. Ongoing efforts to improve “biocompatible” implant materials that reliably integrate with host tissue (Williams 1989) without adverse events have not yet provided ideal materials performance, nor yielded design criteria for engineering this integration. Every material implanted in the body elicits some type of graded foreign body response (FBR), an abnormal and unresolved host healing response tolerated over the life of the host, or a clinical nightmare if suf ciently adverse.
