3D bioprinted scaffolds for diabetic wound-healing applications

The treatment strategy required for the effective healing of diabetic foot ulcer (DFU) is a complex process that is requiring several combined therapeutic approaches. As a result, there is a significant clinical and economic burden associated in treating DFU. Furthermore, these treatments are often unsuccessful, commonly resulting in lower-limb amputation. The use of drug-loaded scaffolds to treat DFU has previously been investigated using electrospinning and fused deposition modelling (FDM) 3D printing techniques; however, the rapidly evolving field of bioprinting is creating new opportunities for innovation within this research area. In this study, 3D-bioprinted scaffolds with different designs have been fabricated for the delivery of an antibiotic (levoflocixin) to DFU. The scaffolds were fully characterised by a variety of techniques (e.g. SEM, DSC/TGA, FTIR, and mechanical characterisation), demonstrating excellent mechanical properties and providing sustained drug release for 4 weeks. This proof of concept study demonstrates the innovative potential of bioprinting technologies in fabrication of antibiotic scaffolds for the treatment of DFU. Graphical abstract

On the Development of a Release Mechanism for a Split Hopkinson Tension and Compression Bar

Split Hopkinson bars are used for the dynamic mechanical characterisation of materials under high strain rates. Many of these test benches are designed in such a way that they can either be used for compressive or tensile loading. The goal of the present work is to develop a release mechanism for an elastically pre-stressed Split Hopkinson bar that can be universally used for tensile or compressive loading. The paper describes the design and dimensioning of the release mechanism, including the brittle failing wear parts from ultra-high strength steel. Additionally, a numerical study on the effect of the time-to-full-release on the pulse-shape and pulse-rising time was conducted. The results of the analytical dimensioning approaches for the release mechanism, including the wear parts, were validated against experimental tests. It can be demonstrated that the designed release concept leads to sufficiently short and reproducible pulse rising times of roughly 0.11 ms to 0.21 ms, depending on the pre-loading level for both the tension and compression wave. According to literature, the usual pulse rising times can range from 0.01 ms to 0.35 ms, which leads to the conclusion that a good average pulse rising time was achieved with the present release system.

CFRP Laminates with Recycled Carbon Fiber: Resin Infusion and Mechanical Characterisation

The possibility to produce new components using reclaimed non-woven carbon fabric has been investigated. Being composite waste production increased, different strategies and technologies for recycling are developing to face criticalities and economic aspects related to their disposal. In this scenario, CFRP laminates with recycled carbon fiber and epoxy vinyl ester resin have been fabricated by Resin Infusion under Flexible Tooling (RIFT) and mechanical characterization has been performed to investigate their behavior under tensile, flexural and macro-indentation loads.