An in vitro model system based on calcium- and phosphate ion-induced hMSC spheroid mineralization.

A challenge in regenerative medicine is creating the three-dimensional organic and inorganic in vitro microenvironment of bone, which would allow the study of musculoskeletal disorders and the generation of building blocks for bone regeneration. This study presents a microwell-based platform for creating spheroids of human mesenchymal stromal cells, which are then mineralized using ionic calcium and phosphate supplementation. The resulting mineralized spheroids promote an osteogenic gene expression profile through the influence of the spheroids' biophysical environment and inorganic signaling and require less calcium or phosphate to achieve mineralization compared to a monolayer culture. We found that mineralized spheroids represent an in vitro model for studying small molecule perturbations and extracellular mediated calcification. Furthermore, we demonstrate that understanding pathway signaling elicited by the spheroid environment allows mimicking these pathways in traditional monolayer culture, enabling similar rapid mineralization events. In sum, this study demonstrates the rapid generation and employment of a mineralized cell model system for regenerative medicine applications.

Physical, mechanical and biological performance of PHB-Chitosan/MWCNTs nanocomposite coating deposited on bioglass based scaffold: Potential application in bone tissue engineering.

Nowadays, using the nanocomposite coatings on bioceramic scaffolds is a great interest for many researchers to improve the properties of these scaffolds. In this study, the effect of poly (3-hydroxybutyrate) PHB-Chitosan (Cs)/multi-walled carbon nanotubes (MWCNTs) nanocomposite coating deposited on nano-bioglass (nBG)-titania (nTiO2) scaffolds fabricated by foam replication method was investigated. Structural analyses such as XRD and FT-IR confirmed the presence of PHB, Cs and MWCNTs in the coated scaffolds. The results of SEM and porosity measurement showed that even with 1 wt% MWCNTs, scaffolds have a high percentage of interconnected porosity. The compressive strength of the scaffolds coated with PHB-Cs/MWCNTs (1 wt%) was increased up to 30 folds compared to nBG/nTiO2 scaffold. The surface roughness of the coated scaffolds, which was determined by AFM, was increased. The nanocomposite coating caused a decrease in contact angle and retaining the negative zeta potential of the coated scaffolds. The increase in pH and degradation rate was observed in the coated scaffolds. Increasing the apatite-like formation by the presence of PHB-Cs/MWCNTs was confirmed by SEM, EDAX and XRD tests. PHB-Chitosan/MWCNTs nanocomposite coating lead to more proliferation and viability of MG-63 cells and higher secretion of alkaline phosphatase.