Super-Hydrophilic Coatings for Titanium Implants – Nanostructured Hydroxyapatite

By AZoNano.com Staff Writers

Topics Covered

Introduction
HAnano Surface Coating
HAnano Surface for Improved Wettability
Better Integration between Implant and Bone
Conclusion
About Promimic AB

Introduction

Hydroxyapatite ( HA), which forms the main component of the hard structures in the bone, has long been used as a coating material in the implant industry. For improved integration, layers of more than 20 µm of HA are positioned on the implant. However, this coating technique has certain disadvantages such as increased susceptibility to bacterial infection, non-homogeneous coating thickness and easy exfoliation of the coating layer.

HAnano Surface Coating

The HAnano Surface is a unique HA coating with a layer thickness of only 20 nm and can be applied to any type of implant material, thanks to Promimic's novel wet chemical coating technology. The HA coating procedure is optimized to sustain the underlying surface structure and produces an even layer of HA across the entire surface of the implant. Since the HA particles form an extremely thin layer, the risk of particle exfoliation can be avoided.

Figure 1. HAnano Surface consists of crystalline needle-shaped, nanometer sized hydroxyapatite particles, which perfectly follow the implant surface.

HAnano Surface for Improved Wettability

The HAnano Surface enhances the wettability of the underlying substrate. The image shown below illustrates the difference in wettability between a HAnano Surface coated titanium disc (to the right) and an unmodified titanium disc (to the left).

Figure 2. Presence of the HAnano Surface changes the surface to a super hydrophilic surface

Titanium is a hydrophilic material; however when it is coated with the HAnano Surface a super-hydrophilic surface is achieved. When the titanium implant is coated with the HAnanoSurface, the contact angle is considerably decreased from 50° to less than 10°. The HAnano Surface is comprised of nanometer-sized hydroxyapatite particles that imitate the natural bone minerals and renders a familiar surface for bone cells.

Better Integration between Implant and Bone

The HAnano Surface has been studied and proven in more than 10 pre-clinical in vivo studies. The collective results from these studies demonstrate that the HAnano Surface speeds up and enhances the integration between bone and implant.

A removal torque study was conducted in rabbit and results from this research demonstrate an average of 33% higher removal torque for HAnano Surface coated and  blasted titanium implants after a period of six weeks, when compared to non-modified titanium implants (Figure 3). Since the HAnano Surface is  an extremely thin coating, it considerably enhances the growth of bone cells on the surface, and this in turn promotes a rapid osseointegration and stronger anchoring of the implant.

Figure 3. Removal torque study

Histology images obtained from the same study validate that when the HAnano Surface is applied to an implant, it promotes an enhanced biological response (Figure 4). The micro-sized HA particles attract bone cells to the surface of the implants, which results in increased Bone to Implant Contact (BIC).

Figure 4. Coating of an implant with the HAnano Surface gives rise to an improved biological response

Conclusion

When the HAnano Surface is applied to titanium, an implant with favourable properties such as increased interfacial area, and super-hydrophilicity can be formed. These advantageous properties have shown to enhance anchoring strength and accelerate the osseointegration. Furthermore, the HAnano Surface creates a substrate with bone like chemistry without affecting the surface roughness.

About Promimic AB

Promimic is a biomaterial company founded in 2004 as a spin-off from research performed at Chalmers University of Technology in Gothenburg, Sweden. The company develops and markets a new generation of implant surface modifications and synthetic bone based on a patented method for production of nano sized hydroxyapatite. Promimic has an innovative and experienced organization that continuously is working on new ways to improve surface modification and coating of new materials.

  • HAnano Surface is a unique implant surface which dramatically accelerates osseointegration. The surface can be applied onto various types of materials - including metals, ceramics and polymers - regardless of its dimensions and structure. The HAnano Surface has received 510(k) approval by the FDA (American Food and Drug Administration), which applies to the area of dental implants.
  • HAnano Bone is a new generation of synthetic bone. The unique composition of HAnano Bone allows it to be mouldable over extended periods of time.

This information has been sourced, reviewed and adapted from materials provided by Promimic AB.

For more information on this source, please visit Promimic AB.

Date Added: Aug 29, 2013 | Updated: Sep 5, 2013
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