Biomedical engineers at Purdue University have proven that bone cells attach better to metals with nanometer-scale surface features, offering hope for improved prosthetic hips, knees and other implants.
Conventional titanium alloys used in hip and knee replacements are relatively smooth and the body often reacts to these areas, as it would to any foreign invader, by covering the parts with a fibrous tissue intended to remove the unwanted material. The fibrous tissue prevents prostheses from making good contact with the body by getting between prosthetic devices and damaged body parts. This in turn impedes their performance.
By covering the implant materials with nanometer-scale bumps, Thomas Webster, an assistant professor of biomedical engineering, and postdoctoral researcher Jeremiah Ejiofor, have shown that not only can it keep the body from rejecting artificial parts but that the tiny bumps stimulate the body to regrow bone and other types of tissue.
Compared with titanium alloy covered in micron-sized bumps, about 60% more new cells are grown on the same alloy containing nanometer-scale features. The hope is that these experiments will lead to longer lasting and more natural implants.