Influence of Strontium on the Biological Behavior of Bioactive Glasses for Bone Regeneration

Bioactive glasses (BGs) can potentially be applied in biomedicine, mainly for bone repair and replacement, given their unique ability to connect to natural bone tissue and stimulate bone regeneration. Since their discovery, several glass compositions have been developed to improve the properties and clinical abilities of traditional bioactive glass. Different inorganic ions, such as strontium (Sr2+), have been incorporated in BG due to their ability to perform therapeutic functions. Sr2+ has been gaining prominence due to its ability to stimulate osteogenesis, providing an appropriate environment to improve bone regeneration, in addition to its antibacterial potential. However, as there are still points in the literature that are not well consolidated, such as the influence of ionic concentrations and the BG production technique, this review aims to collect information on the state of the art of the biological behavior of BGs containing Sr2+. It also aims to gather data on different types of BGs doped with different concentrations of Sr2+, and to highlight the manufacturing techniques used in order to analyze the influence of the incorporation of this ion for bone regeneration purposes.

Enhanced proliferation and osteogenic differentiation of MC3T3-E1 pre-osteoblasts on graphene oxide-impregnated PLGA–gelatin nanocomposite fibrous membranes

Currently, combining biodegradable polymeric scaffolds with living cells for bone repair has received significant attention.

Improvement in degradability of 58s glass scaffolds by ZnO and β-TCP modification

58s bioactive glass shows great potential for bone defects repair. However, at early repairing stage, the degradation rate of 58s glass is too fast due to the fast ion-exchange. At later repairing stage, the degradation rate of 58s glass is too slow due to the high dense mineral layer. In this work, Zinc oxide (ZnO) and β-tricalcium phosphate (β-TCP) were introduced into 58s glass bone scaffolds to improve the degradability. The results showed that ZnO could decrease the degradation rate and promote the stability of 58s glass at early repairing stage. Moreover, the presence of β-TCP appeared to increase the degradation rate at a later stage of repairing. Furthermore, in vitro biocompatibility study, carried out using human osteoblast-like cells (MG63), demonstrated that ZnO and β-TCP enhanced cell attachment and proliferation. The study provided a reference for further research in bone tissue engineering.

Organic/inorganic composite membranes based on poly(L-lactic-co-glycolic acid) and mesoporous silica for effective bone tissue engineering

Fabrication of membranes with excellent biocompatibility and bioactivity remains an important technical challenge in bone tissue engineering. In this paper, poly(l-lactic-co-glycolic acid) (PLGA)-SBA15 (Santa Barbara Amorphous 15) composite membranes were prepared by using an electrospinning technique; PLGA was used as a biocompatible and biodegradable polymer and SBA15 was used as a mesoporous silica. The PLGA-SBA15 composite membrane facilitates the cell attachment and the cell proliferation versus pure PLGA membrane where human bone marrow-derived mesenchymal stem cells (hMSCs) were seeded. Furthermore, the analysis of alkaline phosphatase (ALP) activity indicated that this PLGA-SBA15 composite membrane has better osteogenic induction compared with the pure PLGA membrane. Moreover, the presence of SBA15 increased the loading efficiency of the recombinant human bone morphogenetic protein-2 (rhBMP-2) to the membranes. Furthermore, the composite membrane had optimized sustained release of rhBMP-2. Overall, this PLGA-SBA15 composite is an excellent material for bone tissue engineering.