Topological management of materials at a Micro‐scale is one of the fundamental building principles of nature. This combination of material and structural properties results in marked changes in the properties of solids. Nowadays physicists, chemists, materials scientists and engineers explore those effects by synthesizing, characterizing, and modeling Micro‐lattice materials from all material classes. Applications have been identified in the fields of ultra‐lightweight structures, thermal equipment, electrochemical devices, high absorption capacity and bio‐repair materials. This article aims to review recent progress in the development of such advanced Micro‐lattice materials.
Mesenchymal stem cells have become extremely interesting for regenerative medicine and tissue engineering in the horse. Stem cell therapy has been proven to be a powerful and successful instrument, in particular for the healing of tendon lesions. We pre-differentiated equine adipose-tissue-derived stem cells (ASCs) in a collagen I gel scaffold by applying tensile strain, growth differentiation factors (GDFs) and various oxygen tensions in order to determine the optimal conditions for in vitro differentiation toward the tenogenic lineage. We compared the influence of 3% versus 21% oxygen tension, the use of GDF 5, GDF 6 and GDF 7 and the application of uniaxial tensile strain versus no mechanical stimulation on differentiation results as evaluated by cell morphology and by the expression of the tendon-relevant genes collagen I, collagen III, cartilage oligomeric matrix protein and scleraxis. The best results were obtained with an oxygen tension of 21%, tensile stimulation and supplementation with GDF 5 or GDF 7. This approach raises the hope that the in vivo application of pre-differentiated stem cells will improve healing and recovery time in comparison with treatment involving undifferentiated stem cells.
BackgroundHallux valgus disease is a common deformity of the forefoot. There are currently more than 100 surgical approaches for operative treatment. Because hypermobility of the first tarsometatarsal joint is considered to be causal for hallux valgus disease, fusion of the tarsometatarsal joint is an upcoming surgical procedure. Despite the development of new and increasingly stable fixation devices like different locking plates, malunion rates have been reported in 5 to 15% of cases.MethodsBiomechanical comparison of three commonly used fixation devices (a dorsal locking plate, a plantar locking plate, and an intramedullary fixation device) was performed by weight-bearing simulation tests on synthetic bones. Initial compression force and stiffness during simulation of postoperative weight-bearing were analysed.ResultsFixation of the first tarsometatarsal joint with the plantar plate combination demonstrated a higher stiffness compared to fixation with the intramedullary implant or the medial locking plate. The intramedullary device provided the highest initial compression force. Failure was detected in the following ranking: (1) the angle-stable intramedullary fixation device, (2) the medial located plate, and (3) the plantar locking plate.ConclusionThe intramedullary device demonstrated the highest initial compression force of the three tested implants. The plantar locking plate showed the best overall stability during weight-bearing simulation. Further clinical research is necessary to analyse if the intramedullary fixation device needs a longer period of non-weight-bearing to reach a better non-union rate compared to the plantar locking plate.
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