Jun 6, 2007
A new design of implant surface
Bone implant surfaces harbour a unique environment to stimulate patients' cells, which integrates the titanium (Ti) materials with surrounding bone tissue, forming a connection known as "osseointegration". The new implant-surface design applies nanotechnology concepts and has shown robust biological responses.
Dental implants have been used for replacing missing teeth with impressive clinical outcomes. This is in part due to improved osseointegration to implant surfaces with various micro-topography. However, there are some downsides: patients must spend the long healing time without teeth and when implants are placed in bones other than jawbones, the clinical outcome has been relatively poor.
A new Ti implant surface using nanotechnology-based colloidal nanocrystal self-assembly has been proposed. Hydroxyapatite (HA) crystals are the predominant mineral component of bone tissue and HA derivatives have been widely used as bone filler. What happens if colloidal HA nanocrystals are self-assembled on the implant surface? This study was first conceptualized at Chemat Technology Inc, which has extensive expertise in sol-gel technology but no prior biological experience. After contacting the UCLA Weintraub Center for consultation, Dr Huang and her Chemat team obtained NIH SBIR support and demonstrated the feasibility.
HA coating on Ti implants, which deposits micron to submicron-thick coatings, is not new. The HA colloidal nanocrystal self-assembly did not form these conventional layers but rather deposited HA nanocrystals on the Ti substrate with discrete spacing. As a result, the novel nano-topography was generated.
The experimental implant was manufactured by discrete nanocrystal deposition on the implant surface with predisposing micro-topography by double acid-etching (DAE). When the experimental implant was placed in a rat femur, the degree of osseointegration increased 129% over DAE implants, and 782% over smooth-surface implants. A commercial application has already materialized, demonstrating the versatility of this nanotechnology.
About the author
Ichiro Nishimura is a professor in the Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry at UCLA School of Dentistry, and has served as the founding director of the Weintraub Center for Reconstructive Biotechnology. The Weintraub Center's mission is to improve the quality of life of patients suffering from facial disfigurement and functional loss due to cancer and oral diseases. His current research focuses on the biotechnology of tissue engineering and wound healing, in which application of nanotechnology has increasingly become essential.