Additively Manufactured Biodegradable Porous Zinc Implants for Orthopeadic Applications

Abstract (2021)

Authors

P. Pavanram University Hospital RWTH Aachen
Y. Li Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
H. Jahr Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
J. Zhou Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
Yusuke Kubo University Hospital RWTH Aachen
Karel Lietaert Katholieke Universiteit Leuven, University Hospital RWTH Aachen
Sander A. Leeflang Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
M.A. Leeflang Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
L.I. Fockaert Team Arjan Mol - Mechanical, Maritime and Materials Engineering
B. Pouran Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
J.M.C. Mol Team Arjan Mol - Mechanical, Maritime and Materials Engineering
Harrie Weinans Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
HH Weinans Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
H. Weinans Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering
Research Group
Biomaterials & Tissue Biomechanics (Mechanical, Maritime and Materials Engineering) (TU Delft)
More Info
expand_more

Published Date

2021

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Faculty

Mechanical, Maritime and Materials Engineering

Department

Biomechanical Engineering

Research Group

Biomaterials & Tissue Biomechanics

Abstract

As compared to magnesium (Mg) and iron (Fe), solid zinc (Zn)-based absorbable implants show better degradation rates. An ideal bone substitute should provide sufficient mechanical support, but pure Zn itself is not strong enough for load-bearing medical applications. Modern processing techniques, like additive manufacturing (AM), can improve mechanical strength of Zn. To better mimic the in vivo situation in the human body, we evaluated the degradation behavior of porous Zn implants in vitro under dynamic conditions. Our study applied selective laser melting (SLM) to build topographically ordered absorbable Zn implants with superior mechanical properties. Specimens were fabricated from pure Zn powder using SLM and diamond unit cell topological design. In vitro degradation was performed under both static and dynamic conditions in a custom-built set-up under cell culture conditions (37 °C, 20% O2 and 5% CO2) for up to 28 days. Mechanical properties of the porous structures were determined according to ISO 13314: 2011 at different immersion time points. Modified ISO 10993 standards were used to evaluate biocompatibility through direct cell seeding and indirect extract-based cytotoxicity tests (MTS assay, Promega) against identically designed porous titanium (Ti-6Al-4V) specimens as reference material. Twenty-four hours after cell seeding, its efficacy was evaluated by Live-Dead staining (Abcam) and further analyzed using dual channel fluorescent optical imaging (FOI) and subsequent flow cytometric quantification. Porous Zn implants were successfully produced by means of SLM with a yield strength and Young's modulus in the range of 3.9–9.6 MPa and 265–570 MPa, respectively. Dynamic flow significantly increased the degradation rate of AM porous Zn after 28 days. Results from Zn extracts were similar to Ti-6Al-4V with >95% of cellular activity at all tested time points, confirming level 0 cytotoxicity (i.e., This study clearly shows the great potential of AM porous Zn as a bone substituting material. Moreover, we demonstrate that complex topological design permits control of mechanical properties and degradation behavior.