Natural bone regeneration

Most of the bio-nanocomposites tested as implants for bone regeneration are based on the assembly of HAP nanoparticles with collagen, trying to reproduce the composition, biocompatibility and suitable mechanical properties of natural bone. 

These polymeric materials are fabricated to mimic the shape of natural bone, in a form referred to as a scaffolding. The scaffolding provides open spaces in which the body s osteoblasts can begin the regeneration of new hone. When regeneration is complete, the new bone can take over the structural chores temporarily performed by the bone implant. 

Use of 3D foams is also a popular method for bone regeneration applications, although they are most often employed for trabecular bone regeneration [152,154]. There are a few methods utilized to create foams for this application, one of the most popular being a polymer foam replication technique, in which a polymer foam is either electrosprayed or immersed into a HAp/bioactive glass particle slurry in order to fully coat the foam and create a trabecular bone-like aichitecture. However, other methods are also utilized, including creating composite foam solutions that are injectable and form once inside the body [153]. Results of Fu et al. [152] have indicated mechanical properties similar to those of natural trabecular bone. 

Autografts are bone tissue harvested from a donor site within the same individual (typically from the iliac crest of the pelvis) and transplanted to the fracture site. The innately autologous nature of these scaffolds combined with their highly osteoinductive properties has led them to be considered the gold standard . However, while they are useful for providing a filler material that is conducive to bone regeneration without any risk of rejection, material is limited and the removal of bone from the donor site often results in residual pain and morbidity [28]. 

Petite, H., Viateau, V., Bensaid, W., Meunier, A. de, Poliak, C., Bourguignon, M., Gudina, K Sedel, L., and Guillemin, G. (2000), Tissue-engineered bone regeneration. Nature Biotechnol. 18(9) 959-963. 

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