The Prospects of Zinc as a Structural Material for Biodegradable Implants—A Review Paper
Department of Materials Engineering, Ben-Gurion University of the Negev, P.O. Box 652, 8410501 Beer-Sheva, Israel
Biomedical Engineering Department, Michigan Technological University, Houghton, MI 49931, USA
Author to whom correspondence should be addressed.
Metals 2017, 7(10), 402; https://doi.org/10.3390/met7100402
Received: 31 August 2017 / Revised: 21 September 2017 / Accepted: 22 September 2017 / Published: 1 October 2017
(This article belongs to the Special Issue Biodegradable Metals)
In the last decade, iron and magnesium, both pure and alloyed, have been extensively studied as potential biodegradable metals for medical applications. However, broad experience with these material systems has uncovered critical limitations in terms of their suitability for clinical applications. Recently, zinc and zinc-based alloys have been proposed as new additions to the list of degradable metals and as promising alternatives to magnesium and iron. The main byproduct of zinc metal corrosion, Zn2+, is highly regulated within physiological systems and plays a critical role in numerous fundamental cellular processes. Zn2+ released from an implant may suppress harmful smooth muscle cells and restenosis in arteries, while stimulating beneficial osteogenesis in bone. An important limitation of pure zinc as a potential biodegradable structural support, however, lies in its low strength (σUTS ~ 30 MPa) and plasticity (ε < 0.25%) that are insufficient for most medical device applications. Developing high strength and ductility zinc with sufficient hardness, while retaining its biocompatibility, is one of the main goals of metallurgical engineering. This paper will review and compare the biocompatibility, corrosion behavior and mechanical properties of pure zinc, as well as currently researched zinc alloys.