Deposition of boron doped DLC films on TiNb and characterization of their mechanical properties and blood compatibility

Shahira Liza; Junko Hieda; Hiroki Akasaka; Naoto Ohtake; Yusuke Tsutsumi; Akiko Nagai; Takao Hanawa

doi:10.1080/14686996.2016.1262196

Deposition of boron doped DLC films on TiNb and characterization of their mechanical properties and blood compatibility

Sci Technol Adv Mater. 2017 Jan 16;18(1):76-87. doi: 10.1080/14686996.2016.1262196. eCollection 2017.

Authors

Shahira Liza¹, Junko Hieda², Hiroki Akasaka², Naoto Ohtake², Yusuke Tsutsumi³, Akiko Nagai³, Takao Hanawa³

Affiliations

¹ Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, Tokyo, Japan; Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia.
² Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology , Tokyo , Japan.
³ Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University , Tokyo , Japan.

Abstract

Diamond-like carbon (DLC) material is used in blood contacting devices as the surface coating material because of the antithrombogenicity behavior which helps to inhibit platelet adhesion and activation. In this study, DLC films were doped with boron during pulsed plasma chemical vapor deposition (CVD) to improve the blood compatibility. The ratio of boron to carbon (B/C) was varied from 0 to 0.4 in the film by adjusting the flow rate of trimethylboron and acetylene. Tribological tests indicated that boron doping with a low B/C ratio of 0.03 is beneficial for reducing friction (μ = 0.1), lowering hardness and slightly increasing wear rate compared to undoped DLC films. The B/C ratio in the film of 0.03 and 0.4 exhibited highly hydrophilic surface owing to their high wettability and high surface energy. An in vitro platelet adhesion experiment was conducted to compare the blood compatibility of TiNb substrates before and after coating with undoped and boron doped DLC. Films with highly hydrophilic surface enhanced the blood compatibility of TiNb, and the best results were obtained for DLC with the B/C ratio of 0.03. Boron doped DLC films are promising surface coatings for blood contacting devices.

Keywords: 10 Engineering and structural materials; 104 Carbon and related materials; 306 Thin film / Coatings; Boron doped DLC film; platelet adhesion and activation; surface energy; thin film; tribology; wettability.