Scaffolds and coatings for bone regeneration

Abstract

Bone tissue has an astonishing self-healing capacity yet only for non-critical size defects (<6 mm) and clinical intervention is needed for critical-size defects and beyond that along with non-union bone fractures and bone defects larger than critical size represent a major healthcare problem. Autografts are, still, being used as preferred to treat large bone defects. Mostly, due to the presence of living differentiated and progenitor cells, its osteogenic, osteoinductive and osteoconductive properties that allow osteogenesis, vascularization, and provide structural support. Bone tissue engineering strategies have been proposed to overcome the limited supply of grafts. Complete and successful bone regeneration can be influenced by several factors namely: the age of the patient, health, gender and is expected that the ideal scaffold for bone regeneration combines factors such as bioactivity and osteoinductivity. The commercially available products have as their main function the replacement of bone. Moreover, scaffolds still present limitations including poor osteointegration and limited vascularization. The introduction of pores in scaffolds are being used to promote the osteointegration as it allows cell and vessel infiltration. Moreover, combinations with growth factors or coatings have been explored as they can improve the osteoconductive and osteoinductive properties of the scaffold. This review focuses on the bone defects treatments and on the research of scaffolds for bone regeneration. Moreover, it summarizes the latest progress in the development of coatings used in bone tissue engineering. Despite the interesting advances which include the development of hybrid scaffolds, there are still important challenges that need to be addressed in order to fasten translation of scaffolds into the clinical scenario. Finally, we must reflect on the main challenges for bone tissue regeneration. There is a need to achieve a proper mechanical properties to bear the load of movements; have a scaffolds with a structure that fit the bone anatomy. Graphical Abstract* Helena Filipa Pereira

Modifying MSC Phenotype to Facilitate Bone Healing: Biological Approaches

“…Potential approaches include the use of improved scaffolds and addition of exogenous growth factors; however, the most difficult aspect of this equation is to renew or revitalize the host cells locally or provide additional cells of the MSC-osteoblast cell lineage, the endothelial cell lineage, and other cells that could engraft or provide critical signaling mechanisms to enhance bone healing (Prockop, 2009 ). Although there has been extensive literature on the use of bone substitutes, novel scaffolds and growth factors, studies focused on providing or augmenting the deficient cellular components that are needed for bone healing have received less attention (Bravo et al, 2013 ; Park et al, 2018 ; Marongiu et al, 2020 ; Pereira et al, 2020 ).…”

Potential Applications of Magnesium-Based Polymeric Nanocomposites Obtained by Electrospinning Technique

“…Table 3. Requirements for the design of scaffolds in bone tissue engineering [141][142][143][144][145][146][147].…”

Simultaneous Regeneration of Bone and Nerves Through Materials and Architectural Design: Are We There Yet?

“…[ 5 ] Additional materials are required for treating bone defects with a high risk of nonunion (>6 mm in diameter) to re‐establish the functions of the original tissues. [ 6 ] The current gold standard of grafting with autologous bone is faced with the limited availability of donor sites as well as secondary damage or infection. [ 7,8 ] Conversely, the use of allogenic or xenogenic transplants may result in adverse immune responses and disease transmission.…”