The feasibility of eco-friendly electrical discharge machining for surface modification of Ti: A comparison study in surface properties, bioactivity, and cytocompatibility

Yan-Hsiung Wang; Chun-Chung Liao; Yi-Cheng Chen; Shih-Fu Ou; Che-Yu Chiu

doi:10.1016/j.msec.2019.110192

The feasibility of eco-friendly electrical discharge machining for surface modification of Ti: A comparison study in surface properties, bioactivity, and cytocompatibility

Mater Sci Eng C Mater Biol Appl. 2020 Mar:108:110192. doi: 10.1016/j.msec.2019.110192. Epub 2019 Nov 1.

Authors

Yan-Hsiung Wang¹, Chun-Chung Liao², Yi-Cheng Chen², Shih-Fu Ou³, Che-Yu Chiu²

Affiliations

¹ School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, 807, Taiwan; Orthopaedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
² Department of Mold and Die Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, 807, Taiwan.
³ Department of Mold and Die Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, 807, Taiwan. Electronic address: M9203510@nkust.edu.tw.

PMID: 31923966
DOI: 10.1016/j.msec.2019.110192

Abstract

This study provided an eco-friendly manufacturing method for Ti implants by combining machining and surface treatment processes. Ti was machined by electrical discharge machining (EDM) in a water-based dielectric in order to reduce environmental impact and improve operational health. The feasibility of this eco-friendly EDM was evaluated by tested the bioactivity and cytocompatibility of the EDM-treated Ti and the commercially micro-arc oxidation (MAO)-treated Ti was used as a control group. Pulsed MAO and EDM treatments were applied on Ti in an aqueous solution containing hydroxyapatite (HA) with the same concentration (30 g/L) under the same voltage and treatment period. The two surface modification processes were compared from the aspects of surface composition, coating structure, and coating adhesion. Furthermore, in vitro bioactivity and cellular biocompatibility of the MAO- and EDM-treated Ti films were tested. Both treatments produced Ti oxide containing Ca and P on Ti, and the EDM-formed film possessed more Ca, with its Ca/P value closer to HA, as compared to the MAO-formed film. The MAO-formed films had micropores and nanopores in the middle region and film/substrate interface, respectively. Pores only existed on the surface of the EDM-formed films. The MAO-formed films were fractured, but the EDM-formed films maintained their original structure under tensile stress, tested according to the ASTM C633 standard. The bioactivity of the EDM-treated surface was higher than that of the MAO-treated and untreated Ti surface. After 24 h cell incubation, the EDM-treated surface exhibited a significantly higher number of cells than untreated Ti and the MAO-treated surface.

Keywords: Bioactivity; Cytocompatibility; Eco-friendly EDM; Hydroxyapatite; Ti.

Publication types

Comparative Study

MeSH terms

Cell Line
Coated Materials, Biocompatible* / chemistry
Coated Materials, Biocompatible* / pharmacology
Electrochemical Techniques* / instrumentation
Electrochemical Techniques* / methods
Feasibility Studies
Humans
Materials Testing*
Osteoblasts / cytology
Osteoblasts / metabolism*
Oxidation-Reduction
Surface Properties
Titanium* / chemistry
Titanium* / pharmacology

Substances

Coated Materials, Biocompatible
Titanium