Implant-associated infections remain one of the most challenging complications in modern orthopaedic and biomedical procedures. Biofilm formation on implant surfaces protects pathogenic microorganisms from antibiotics and immune responses, often requiring surgical implant removal. Magnetic microrobots have recently emerged as a promising approach for targeted biofilm disruption and localized therapeutic interventions. This thesis investigates the design, fabrication, and experimental evaluation of magnetically actuated microrobots for potential application in the treatment of implant-associated infections. Several microrobot prototypes were designed using computer-aided design and fabricated using different additive manufacturing techniques, including stereolithography, fused deposition modelling, and direct ink writing. The robots incorporated embedded NdFeB permanent magnets to enable actuation under an externally generated rotating magnetic field. Motion experiments were conducted in media of different viscosities (air, water, and glycerin) to evaluate propulsion performance and the influence of geometry, material composition, and fabrication method. Magnetic characterization, X-ray diffraction analysis, and hyperthermia measurements were additionally performed to assess magnetic properties, structural stability, and heating efficiency. The results demonstrate that helical microrobot geometries fabricated using high-resolution printing methods exhibit superior propulsion characteristics in viscous environments. Magnetic hyperthermia experiments confirmed that iron-based structures can generate significant heating under alternating magnetic fields, suggesting potential for combined mechanical and thermal biofilm disruption. The findings highlight both the potential and limitations of current microrobot designs and provide insights for further optimization toward biomedical applications. ... Read more

Over two million bone grafts are performed worldwide, each year. The preferred method is using autografts, but there are two important downsides. There is often insufficient tissue to harvest and the scar at the harvesting side is painfull for the patient. Therefore there exists a great need to improve synthetic grafts.

Traditionally, synthetic bone scaffolds are made from only one material, this can either be a (bioactive) ceramic or metal. The former has the benefit of promoting bone growth, but has insufficient mechanical properties. Metals on the other hand have no issue competing with bone in terms of mechanical properties, but they may not be biocompatible nor aid osteo-induction.

In this study direct ink writing was used to produce multimaterial Ti6Al4V and akermanite scaffolds. The goal was to combine the favourable mechanical properties of Ti6Al4V alloy with the osteo-inductive properties of akermanite. Composites of Ti6Al4V and akermanite were evaluated as well, but similar to akermanite ceramic on itself, their mechanical performance was deemed insufficient. Akermanite and Ti6Al4V was found to react and form titanium silicide and a calicum compound, presumed to be calcium oxide. A core shell scaffold was designed which uses a Ti6Al4V shell and an akermanite composite core in order to achieve both adequate mechanical and improved bioactive properties. This scaffold performed comparable to cortical bone in stiffness, and boasted superior strength. ... Read more