Immobilizing bioactive molecules onto titanium implants to improve osseointegration

Titanium and its alloys are widely used for orthopedic and dental implants, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. Numerous attempts have been made to enhance the osseointegration of titanium implants, including modifications in their surface topography and immobilization of bioactive molecules on their surfaces. This article reviews the various modification techniques pertaining to immobilization of bioactive molecules on titanium implants, including physical adsorption, chemically covalent bonding, and biomimetic incorporation. Recent work has shown that the bioactive properties of titanium implants can be improved selectively by immobilization of the appropriate bioactive molecules, while the desirable bulk attributes of the substrates are retained.

► Titanium and its alloys are widely used for orthopedic and dental implants.
► The proper surface modification techniques could improve osseointegration.
► We review various techniques of immobilizing bioactive molecules on titanium.