In all cases, however, a biomaterial must perform compatibly with the body. In other words, the biocompatibility and in some cases, bioactivity , of the material comprise key factors in determining whether a new graft or implant succeeds in the body. In order to define biocompatibility, it may be easier to define what it is not, rather than what it is. A biocompatible material disrupts normal body functions as little as possible. Therefore, the material causes no thrombogenic , toxic, or allergic inflammatory response when the material is placed in vivo.
Bioactive materials play a more aggressive role in the body.
While a biocompatible material should affect the equilibrium of the body as little as possible, a bioactive material recruits specific interactions between the material and surrounding tissue. For example, a bioactive material can encourage tissue integration to aid in the fixation of an implant in the body. The coating encourages ingrowth from the surrounding tissue that interlocks within the pores much like the pieces of a puzzle lock together. Although many current medical procedures call for inert biocompatible materials, the increasing understanding of tissue interaction promises many more applications for aggressive bioactive materials. Here are a few types of materials that have potential use in biomedical applications.