Reengineered graft copolymers as a potential alternative for the bone tissue engineering application by inducing osteogenic markers expression and biocompatibility

Multifunctional Scaffolds Based on Emulsion and Coaxial Electrospinning Incorporation of Hydroxyapatite for Bone Tissue Regeneration

Tissue engineering is nowadays a powerful tool to restore damaged tissues and recover their normal functionality. Advantages over other current methods are well established, although a continuous evolution is still necessary to improve the final performance and the range of applications. Trends are nowadays focused on the development of multifunctional scaffolds with hierarchical structures and the capability to render a sustained delivery of bioactive molecules under an appropriate stimulus. Nanocomposites incorporating hydroxyapatite nanoparticles (HAp NPs) have a predominant role in bone tissue regeneration due to their high capacity to enhance osteoinduction, osteoconduction, and osteointegration, as well as their encapsulation efficiency and protection capability of bioactive agents. Selection of appropriated polymeric matrices is fundamental and consequently great efforts have been invested to increase the range of properties of available materials through copolymerization, blending, or combining structures constituted by different materials. Scaffolds can be obtained from different processes that differ in characteristics, such as texture or porosity. Probably, electrospinning has the greater relevance, since the obtained nanofiber membranes have a great similarity with the extracellular matrix and, in addition, they can easily incorporate functional and bioactive compounds. Coaxial and emulsion electrospinning processes appear ideal to generate complex systems able to incorporate highly different agents. The present review is mainly focused on the recent works performed with Hap-loaded scaffolds having at least one structural layer composed of core/shell nanofibers.

Rifapentine Polylactic Acid Sustained-Release Microsphere Complex for Spinal Tuberculosis Therapy: Preparation, in vitro and in vivo Studies

Purpose

Spinal tuberculosis has been a common clinical extrapulmonary tuberculosis in recent years. The general anti-tuberculosis drug treatment cycle is long, with unsatisfactory efficacy. This study focused on the preparation and evaluation of rifapentine polylactic acid sustained-release microsphere complex for spinal tuberculosis therapy.

Methods

Rifapentine polylactic acid sustained-release microspheres (RPSMs) were prepared through the double emulsion solvent evaporation method, and RPSMs were combined with hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) composite material to obtain drug-loaded, sustained-release complex. We evaluated the complex for dynamics of drug release and osteogenic ability using in vitro release test, alkaline phosphatase and alizarin red staining, real-time PCR and Western blot. A rabbit model of a spinal tuberculosis defect was established and repaired using HA/β-TCP or complex. The ability of anti-tuberculosis and tissue repair effects of the complex were evaluated through in vivo experiments.

Results

The complex constructed of RPSMs and HA/β-TCP demonstrated a long drug release time, with no significant inhibition of cell osteogenic differentiation in vitro experiments. Postoperative macroscopic observation, immunohistochemical staining and Nilsson histological scores showed that the complex has good effects on the tissue repair. Moreover, the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), important indexes of inflammation, decreased to normal levels in the complex group.

Conclusion

In vitro and in vivo experiments demonstrated that the complex constructed of RPSMs and HA/β-TCP effectively treated spinal tuberculosis. Therefore, the complex represents a promising approach for the treatment of spinal tuberculosis.

Ginseng compound K incorporated porous Chitosan/biphasic calcium phosphate composite microsphere for bone regeneration

There is a substantial for the bone graft materials in the clinical field. Porous, stable and biodegradable bone microsphere scaffold using biopolymer chitosan was studied, and biphasic calcium phosphate was added to improve mechanical and osteoconductivity properties later ginseng compound K was added for improving its medicinal properties. They were characterized using FTIR and XRD that showed the apatite crystal in the composite microsphere scaffolds were structurally similar to that of biogenic apatite crystals. Scanning electron microscopy images confirmed the presence of hydroxyapatite on the surface of the composite microspheres. In vitro results infers that the composite microspheres are biocompatible with NIH 3T3 and MG63 cells and capable of supporting growth and spreading of MG-63 cells. Further, Osteogenic markers expression was found to be higher in rat bone marrow stem cells seeded on microsphere scaffolds compared to control. The prepared biocomposite porous microsphere scaffold developed in this study can be used as an alternative for the bone regeneration or bone tissue engineering.

Human adipose stem cells induced to osteogenic differentiation by an innovative collagen/hydroxylapatite hybrid scaffold

Novel biomaterials are of paramount importance for bone regrowth. In this study, we investigated human adipose stem cells (hASCs) for osteogenic, osteoconductivity, and osteoinductivity effects of an innovative collagen/hydroxylapatite hybrid scaffold. In hASCs that were grown on this scaffold, osteogenic genes were analyzed for their expression profiles, together with adhesion and extracellular matrix genes. In hASC integrins, basement membrane constituents and collagens were up-regulated, together with cell proliferation. In addition, expression of osteopontin and activated focal adhesion kinase was studied at the protein level. Our in vitro data indicate that hASCs, together with hybrid biomaterial, is an important model of study to investigate in vitro bone induction.-Mazzoni, E., D'Agostino, A., Manfrini, M., Maniero, S., Puozzo, A., Bassi, E., Marsico, S., Fortini, C., Trevisiol, L., Patergnani, S., Tognon, M. Human adipose stem cells induced to osteogenic differentiation by an innovative collagen/hydroxylapatite hybrid scaffold.