Biocompatibility

In practice, biocompatibility necessitates that a biomaterial does not induce an adverse reaction in the body, but it does not need to be inert; it should cause a suitable response if necessary. For example, a bone implant is expected to function without inciting a negative response from the bone. However, most bone plates lead to a depression in the bone tissue onto which they are fixed. This is not biocompatible even though the implant does not incite any carcinogenic, allergic, or immune responses. A PMMA contact lens, which does not transmit sufficient oxygen and causes hypoxia in the corneal tissue under the lens, is not completely biocompatible, while a poly(hydroxyethyl methacrylate) (PHEMA) contact lens that allows plenty of oxygen transfer is more biocompatible.