Desenvolvimento e aplicações de biocerâmica

The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. They are of the special significance for the human beings because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. Therefore, the majority of the artificially prepared calcium orthophosphates of high purity appear to be well tolerated by human tissues in vivo and possess the excellent biocompatibility, osteoconductivity and bioresorbability. These biomedical properties of calcium orthophosphates are widely used to construct bone grafts. In addition, natural calcium orthophosphates are the major source of phosphorus, which are used to produce agricultural fertilizers, detergents and various phosphorus-containing chemicals. Thus, there is a great significance of calcium orthophosphates for the humankind and, here, an overview on the current knowledge on this subject is provided.

Polymeric sintered microsphere scaffolds have shown their tremendous potential in bone tissue engineering applications due to their highly porous and interconnected three dimensional structure and excellent mechanical properties. While these scaffolds are able to support basic cellular activity after seeding cells on them, the bioactivity of these scaffolds in terms of enhancing the biological performance of stem cells during bone regeneration is still under satisfactory. We hypothesized that incorporation of bioactive addictive such as hydroxyapatite into these scaffolds could improve their bioactivity without sacrificing the bulk properties of the scaffolds. We have successfully incorporated nano-hydroxyapatite (n-HA) into poly (lactic acid-glycolic acid) (PLAGA) microsphere based scaffolds in our previous studies. Herein, we aimed to evaluate the bioactivity of PLAGA/n-HA composite scaffolds, with a focus on studying the mineralization of the scaffolds in vitro. The capability of inducing apatite formation in vitro was largely enhanced in the composite scaffolds compared to plain PLAGA scaffolds. More importantly, PLAGA/n-HA composite scaffolds have been shown to improve rabbit mesenchymal stem cells (RMSCs) proliferation, differentiation, and mineralization as compared to control PLAGA scaffolds. Taken together, introduction of n-HA appears to be an efficient approach to improve the bioactivity of PLAGA scaffolds for bone tissue engineering.