Magnesium alloys for orthopedic applications:A review on the mechanisms driving bone healing

Magnesium(Mg) alloys have attracted a wealth of attention in orthopedic fields for their superior mechanical properties, degradability,and excellent biocompatibility. Consistently, to resolve the issues on rapid degradation, more studies are dedicated to the researches on the composition design, preparation and processing, surface modification, the degradation modes of Mg alloys. Nevertheless, the mechanisms by which Mg alloys promote bone healing remain elusive. This review gives an account of specific mechanisms on Mg alloys promoting bone healing from four aspects, immunomodulatory, angiogenesis, osteogenesis and regulation of osteoclast function. We highlight the regulation of Mg alloys on the functional status and interactions of numerous cells that are involved in bone healing, including immune cells, osteogenicrelated cells, osteoclasts, endothelial cells(ECs), nerve cells, etc., and summarize the signaling pathways involved, with the aim to provide the basis and support on future investigation on mechanisms on Mg alloys driving bone regeneration. More importantly, it provides a rationale and a general new basis for the application of Mg alloys in orthopedic fields.

Biomaterials combined with ADSCs for bone tissue engineering:current advances and applications

In recent decades,bone tissue engineering,which is supported by scaffold,seed cells and bioactive molecules(BMs),has provided new hope and direction for treating bone defects.In terms of seed cells,compared to bone marrow mesenchymal stem cells,which were widely utilized in previous years,adipose-derived stem cells(ADSCs)are becoming increasingly favored by researchers due to their abundant sources,easy availability and multi-differentiation potentials.However,there is no systematic theoretical basis for selecting appropriate biomaterials loaded with ADSCs.In this review,the regulatory effects of various biomaterials on the behavior of ADSCs are summarized from four perspectives,including biocompatibility,inflammation regulation,angiogenesis and osteogenesis,to illustrate the potential of combining various materials with ADSCs for the treatment of bone defects.In addition,we conclude the influence of additional application of various BMs on the bone repair effect of ADSCs,in order to provide more evidences and support for the selection or preparation of suitable biomaterials and BMs to work with ADSCs.More importantly,the associated clinical case reports and experiments are generalized to provide additional ideas for the clinical transformation and application of bone tissue engineering loaded with ADSCs.