Bacterial adherence on 3-D printed plasma electrolytic oxidized titanium implants in dynamic conditions

Master thesis (2020)

Authors

I.H.A. Frints Mechanical Engineering

Contributors

I. Apachitei Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering (supervisor 1)
Raymond Bevers Universiteit Maastricht (supervisor 1)
A.A. Zadpoor Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering (supervisor 1)
J.J. van den Dobbelsteen Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 2)
Chris Arts Universiteit Maastricht (supervisor 1)
Faculty
Mechanical Engineering
Copyright: © 2020 Ivo Frints
Bioreactor Biofilm Bone implants Osteoarthritis Biomaterials Implants PEO 3D printed Dynamic Silver Nanoparticles Plasma electrolytic oxidation Antibiotic-Resistant Bacteria Infection Bacterial adhesion Orthopedics Bactericidal
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Published Date

09-09-2020

Language

English

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Faculty

Mechanical Engineering

Abstract

Osteoarthritis, the degeneration of articular cartilage, which causes loss of mobility and chronic pain for patients is a common condition with high clinical demand. Care of this condition currently attributes to ±1.4% of the Dutch annual health care costs, but due to the rapidly aging Dutch population a 41% increase of cases is projected over the next 20 years. Treatment for the most frequently diagnosed forms of osteoarthritis, knee and hip respectively, involves the removal of damaged tissue and placing an artificial total joint replacement (TJR), restoring partial mobility and relieving pain. Despite its success and demand, annually 10% of these treatments are affected by infections or aseptic loosening, which combined with the increase of cases and rapid development of
antibiotic-resistant bacteria requires drastic optimization. Promising strategies that allow infection prevention while assisting the bone-implant fixation are
currently in development, with the common approach consisting of bioactive coatings which enhance the currently applied implants with these antibacterial or bone growth related capabilities. One of these methods in development is the Plasma Electrolytic Oxidation (PEO), which additionally combines morphological changes and chemical biofunctionality by incorporating bioactive elements in the
implants’ surface layer. Until now, antibacterial surfaces bearing silver nanoparticles (AgNPs) have been incorporated into the surfaces of 3D printed titanium implants by PEO but their antibacterial properties have been studied only in static conditions. This study aimed to further characterize the antibacterial effect of these implants by testing their efficacy against bacterial adherence in both dynamic and static conditions. The additive manufactured
Ti-6Al-4V implants were biofunctionalized by PEO with added AgNPs at different concentrations, resulting in non-treated, PEO treated, PEO + 0.3 g/l AgNPs and PEO + 3.0 g/l AgNPs implants. These implants were characterized to relate these to previous PEO implant related studies. During this study, the Centers for Disease Control and Prevention (CDC) bioreactor model was adjusted to fit these PEO + AgNPs implants and test them in conditions of bacterial adherence. Robustness and bacterial adherence were optimized for this adjusted method, where despite thorough troubleshooting inconsistent behaviour was found in the bacterial concentrations in the reactor media in an illogical manner. Dynamic conditions of this reactor caused by the fluid flow were analysed by simulation, this resulted in a calculated shear stress of 0.0058 dynes/cm2, akin to the lower limit magnitude of shear stresses caused by interstitial fluid. Despite shortage of results due to the omitted inconsistent experiments combined with the lost data due to force majeure (COVID-19), a higher bacterial adherence was examined in dynamic conditions compared to static conditions.