Deposition of discrete nanoparticles on an implant surface

• US 8,486,483 B2
• Filed: 11/13/2006
• Issued: 07/16/2013
• Est. Priority Date: 11/14/2005
• Status: Active Grant

• Current Assignee: Biomet 3i LLC (Zimvie Incorporated)
• Original Assignee: Biomet 3i LLC (Zimvie Incorporated)
• Inventors: Berckmans, Bruce III, Towse, Ross W., Mayfield, Robert L.
• Primary Examiner(s): Rodriguez, Cris L
• Assistant Examiner(s): ROSEN, ERIC J
• Application Number:
  US11/598,614
• Publication Number:
  US 20070112353A1
• Time in Patent Office: 2,437 Days
• Field of Search: 433/174, 433/173, 427/2.13, 427/2.1, 427/2.12, 501/1, 977/847, 977/919, 977/931
• US Class Current: 427/2.12
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61C 2008/0046 Textured surface, e.g. roughness, microstructure A61C8/0013 takes precedence
• CPC Class Codes: A61C 8/0006 Periodontal tissue or bone regeneration support means for endoprosthetic bone substitute or bone graft implants A61F2/2846
• CPC Class Codes: A61C 8/0012 characterised by the material or composition, e.g. ceramics, surface layer, metal alloy use of specific materials A61K6/00
• CPC Class Codes: A61C 8/0013 with a surface layer, coating
• CPC Class Codes: A61C 8/0015 being a conversion layer, e.g. oxide layer
• CPC Class Codes: A61C 8/0022 Self-screwing A61C8/0028 takes precedence
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2002/30925 etched
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00059 Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00131 Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00796 Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61K 6/838 Phosphorus compounds, e.g. apatite
• CPC Class Codes: A61K 6/84 comprising metals or alloys
• CPC Class Codes: A61L 2400/12 Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
• CPC Class Codes: A61L 27/06 : Titanium or titanium alloys
• CPC Class Codes: A61L 27/10 : Ceramics or glasses
• CPC Class Codes: A61L 27/32 : Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: C23C 22/03 : containing phosphorus compounds
• CPC Class Codes: C23C 26/00 : Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: C23C 30/00 : Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23G 1/106 : refractory metals

Abstract

A method of forming a nanocrystalline surface on an implant. The method includes the act of roughening at least a portion of the implant surface to form a roughened surface. The method further includes the act of, without forming an alkoxide on the roughened surface, depositing nanocrystals on the roughened surface. The nanocrystals include a material having a property that promotes osseointegration.

Claims

1. A method of forming a nanocrystalline surface on a metallic implant, the implant being made of a material comprising titanium, the method comprising the acts of:

roughening at least a portion of the implant surface to form a roughened surface; and

without forming an alkoxide on the roughened surface, depositing discrete hydroxyapatite nanocrystals directly on the roughened surface by directly contacting an exposed, outer surface of the implant with a solution, the exposed, outer surface of the implant including titanium hydroxide and/or titanium oxide, the solution comprising 2-methoxyethanol solvent and hydroxyapatite nanoparticles, the nanocrystals being on the order of about 20 nanometers to about 100 nanometers, wherein a portion of the roughened surface is exposed between at least some of the discrete nanocrystals such that the exposed roughened portion between the discrete nanocrystals is for contacting bone.

2. The method of claim 1, wherein the act of depositing the hydroxyapatite nanocrystals further comprises adjusting the pH of the solution to achieve a desired deposition of discrete hydroxyapatite nanocrystals.

3. The method of claim 2, wherein the adjusting the pH of the solution includes using ammonium hydroxide.

4. The method of claim 2, wherein the pH is adjusted to between about 9 and about 11.

5. The method of claim 1, wherein the discrete nanocrystals directly bond to the titanium oxide or titanium hydroxide.

6. The method of claim 1, wherein the implant is a dental implant.

7. The method of claim 6, wherein the portion of the implant surface is a threaded bottom portion for facilitating bonding with bone.

8. The method of claim 1, wherein the act of roughening the implant surface comprises:

removing a native oxide layer from the implant surface; and

acid etching the resulting surface.

9. The method of claim 1, wherein the act of roughening the implant surface creates irregularities, the irregularities having peak-to-valley heights not greater than about 20 microns.

10. The method of claim 1 further comprising the act of rinsing the implant in reverse osmosis water, deionized water, or a combination of reverse osmosis water and deionized water.

11. The method of claim 10 further comprising thermally curing the implant to sinter the deposited hydroxyapatite nanocrystals.

12. The method of claim 1 further comprising the acts of:

rinsing the implant in deionized water; and

drying the implant.

13. The method of claim 1, wherein prior to depositing the hydroxyapatite nanocrystals, the method comprises rinsing the implant in deionized water.

14. The method of claim 1, wherein the act of roughening at least a portion of the implant surface includes grit blasting.

15. The method of claim 1, wherein the discrete hydroxyapatite nanocrystals can be viewed using a scanning electron microscope image at magnifications of 10 k×

or greater.

16. The method of claim 1, further comprising adjusting at least one of (a) the immersion time of the implant in the solution, (b) the concentration of the hydroxyapatite nanoparticles in the solution, and (c) the pH of the solution such that discrete hydroxyapatite nanocrystals are deposited on the roughened surface.

17. A method of forming a nanocrystalline surface on an implant, the method comprising the acts of:

providing a metal substrate;

immersing at least a portion of the substrate in a colloidal solution such that the colloidal solution directly contacts an exposed outer surface of the metal substrate, the colloidal solution having a temperature ranging from about 18°

C. to about 32°

C. for about 11.5 minutes to about 240 minutes, the colloidal solution comprising;

a 2-methoxyethanol solvent, and

a plurality of hydroxyapatite nanocrystals having a concentration ranging from about 0.01 weight percent to about 1 weight percent relative to the overall solution; and

adjusting the pH of the colloidal solution to about 9 to about 11,

wherein a portion of the exposed outer surface of the metal substrate is exposed between at least some of the hydroxyapatite nanocrystals such that the exposed portion between the discrete nanocrystals is for contacting bone.

18. A method of forming a nanocrystalline surface on an implant made of a material comprising titanium, the method comprising the acts of:

roughening at least a portion of the implant surface to form a roughened surface; and

immersing at least a portion of the roughened implant surface in a solution including 2-methoxyethanol solvent and hydroxyapatite nanoparticles such that the exposed, roughened surface directly contacts the solution, the exposed, roughened surface including titanium hydroxide and/or titanium oxide, at least one of (a) the immersion time, (b) the concentration of the hydroxyapatite nanoparticles in the solution, and (c) the pH of the solution being selected such that discrete hydroxyapatite nanocrystals are deposited on the roughened surface, a portion of the roughened surface being exposed between at least some of the discrete nanocrystals such that the exposed roughened portion between the discrete nanocrystals is for contacting bone.