Electrochemically assisted deposition of hydroxyapatite on Ti6Al4V substrates covered by CVD diamond films - Coating characterization and first cell biological results

Paulina Strąkowska; René Beutner; Marcin Gnyba; Andrzej Zielinski; Dieter Scharnweber

doi:10.1016/j.msec.2015.10.063

Electrochemically assisted deposition of hydroxyapatite on Ti6Al4V substrates covered by CVD diamond films - Coating characterization and first cell biological results

Mater Sci Eng C Mater Biol Appl. 2016 Feb:59:624-635. doi: 10.1016/j.msec.2015.10.063. Epub 2015 Oct 22.

Authors

Paulina Strąkowska¹, René Beutner², Marcin Gnyba³, Andrzej Zielinski⁴, Dieter Scharnweber⁵

Affiliations

¹ Gdańsk University of Technology, Mechanical Engineering Faculty, Poland; Gdańsk University of Technology, Faculty of Electronics, Telecommunications, and Informatics, Poland.
² Max Bergmann Center, Technische Universität Dresden, Germany.
³ Gdańsk University of Technology, Faculty of Electronics, Telecommunications, and Informatics, Poland.
⁴ Gdańsk University of Technology, Mechanical Engineering Faculty, Poland.
⁵ Max Bergmann Center, Technische Universität Dresden, Germany. Electronic address: Dieter.Scharnweber@tu-dresden.de.

PMID: 26652416
DOI: 10.1016/j.msec.2015.10.063

Abstract

Although titanium and its alloys are widely used as implant material for orthopedic and dental applications they show only limited corrosion stability and osseointegration in different cases. The aim of the presented research was to develop and characterize a novel surface modification system from a thin diamond base layer and a hydroxyapatite (HAp) top coating deposited on the alloy Ti6Al4V widely used for implants in contact with bone. This coating system is expected to improve both the long-term corrosion behavior and the biocompatibility and bioactivity of respective surfaces. The diamond base films were obtained by Microwave Plasma Assisted Chemical Vapor Deposition (MW-PACVD); the HAp coatings were formed in aqueous solutions by electrochemically assisted deposition (ECAD) at varying polarization parameters. Scanning electron microscopy (SEM), Raman microscopy, and electrical conductivity measurements were applied to characterize the generated surface states; the calcium phosphate coatings were additionally chemically analyzed for their composition. The biological properties of the coating system were assessed using hMSC cells analyzing for cell adhesion, proliferation, and osteogenic differentiation. Varying MW-PACVD process conditions resulted in composite coatings containing microcrystalline diamond (MCD/Ti-C), nanocrystalline diamond (NCD), and boron-doped nanocrystalline diamond (B-NCD) with the NCD coatings being dense and homogeneous and the B-NCD coatings showing increased electrical conductivity. The ECAD process resulted in calcium phosphate coatings from stoichiometric and non-stoichiometric HAp. The deposition of HAp on the B-NCD films run at lower cathodic potentials and resulted both in the highest coating mass and the most homogenous appearance. Initial cell biological investigations showed an improved cell adhesion in the order B-NCD>HAp/B-NCD>uncoated substrate. Cell proliferation was improved for both investigated coatings whereas ALP expression was highest for the uncoated substrate.

Keywords: Biological activity; CVD deposition; Diamond films; ECAD deposition; Hydroxyapatite coatings; Ti alloys.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Alloys
Cell Proliferation / drug effects
Cells, Cultured
Coated Materials, Biocompatible / chemistry*
Coated Materials, Biocompatible / pharmacology
Diamond / chemistry*
Durapatite / chemistry*
Electrochemical Techniques / methods*
Humans
Male
Mesenchymal Stem Cells
Titanium / chemistry*
Young Adult

Substances

Alloys
Coated Materials, Biocompatible
titanium alloy (TiAl6V4)
Diamond
Durapatite
Titanium