Fabrication of PCL/PVP Electrospun Fibers loaded with Trans-anethole for Bone Regeneration in vitro.

Trans-anethole (TA) is a phenolic phytocompound widely used in the food and health sector because of its diverse biological properties. However, its role in the promotion of bone formation is not known. With the enhanced bioavailability of TA, we aimed to determine its effect on osteogenesis; TA at different concentrations (5, 10, and 20 µM) was loaded onto polycaprolactone (PCL)/polyvinylpyrrolidone (PVP) fibers by the electrospinning technique. The synthesized PCL/PVP + TA fibers were subjected to physiochemical and material characterization. The addition of TA did not have any effect on fiber thickness, swelling, protein adsorption, degradation, or biomineralization. The fibers were compatible with mouse mesenchymal stem cells (mMSCs). A sustained release of TA from the fibers promoted osteoblast differentiation at the cellular and molecular levels. Furthermore, the release of TA from fibers up-regulated the expression of Runx2, a bone transcription factor, and its co-activators, which are key molecules for osteoblast differentiation. Thus, these results provide insights into the bioavailability of TA in promoting in vitro osteoblast differentiation and the potential applications of TA in bone regeneration.

Bone tissue engineering: Scaffold preparation using chitosan and other biomaterials with different design and fabrication techniques.

In the recent years, a paradigm shift is taking place where metallic/synthetic implants and tissue grafts are being replaced by tissue engineering approach. A well designed three-dimensional scaffold is one of the fundamental tools to guide tissue formation in vitro and in vivo. Bone is a highly dynamic and an integrative tissue, and thus enormous efforts have been invested in bone tissue engineering to design a highly porous scaffold which plays a critical role in guiding bone growth and regeneration. Numerous techniques have been developed to fabricate highly interconnected, porous scaffold for bone tissue engineering applications with the help of biomolecules such as chitosan, collagen, gelatin, silk, etc. We aim, in this review, to provide an overview of different types of fabrication techniques for scaffold preparation in bone tissue engineering using biological macromolecules.

Chitosan/nano-hydroxyapatite/nano-zirconium dioxide scaffolds with miR-590-5p for bone regeneration.

Bone tissue engineering (BTE) relies on biocomposite scaffolds and bioactive molecules for bone regeneration. The present study was aimed to synthesize and characterize biocomposite scaffolds containing chitosan (CS), nano-hydroxyapatite (nHAp) and nano­zirconium dioxide (nZrO2) along with microRNA (miRNA) for BTE applications. miRNAs act as post-transcriptional regulator of gene expression. The fabricated biocomposite scaffolds were characterized using SEM, FT-IR and XRD analyses. The effect of a bioactive molecule (miR-590-5p) with scaffolds was tested for osteoblast differentiation at the cellular and molecular levels using mouse mesenchymal stem cells (C3H10T1/2). The results showed that CS/nHAp/nZrO2 scaffolds promoted osteoblast differentiation, and this effect was further increased in the presence of miR-590-5p in C3H10T1/2 cells. Thus, we suggested that CS/nHAp/nZrO2 scaffolds with miR-590-5p would have potential towards the treatment of bone defects.

Proliferation and differentiation of mesenchymal stem cells on scaffolds containing chitosan, calcium polyphosphate and pigeonite for bone tissue engineering.

OBJECTIVES: Treatment of critical-sized bone defects with cells and biomaterials offers an efficient alternative to traditional bone grafts. Chitosan (CS) is a natural biopolymer that acts as a scaffold in bone tissue engineering (BTE). Polyphosphate (PolyP), recently identified as an inorganic polymer, acts as a potential bone morphogenetic material, whereas pigeonite (Pg) is a novel iron-containing ceramic. In this study, we prepared and characterized scaffolds containing CS, calcium polyphosphate (CaPP) and Pg particles for bone formation in vitro and in vivo. MATERIALS AND METHODS: Chitosan/CaPP scaffolds and CS/CaPP scaffolds containing varied concentrations of Pg particles (0.25%, 0.5%, 0.75% and 1%) were prepared and characterized by SEM, XRD, EDAX, FT-IR, degradation, protein adsorption, mechanical strength and biomineralization studies. The cytocompatibility of these scaffolds with mouse mesenchymal stem cells (mMSCs, C3H10T1/2) was determined by MTT assay and fluorescence staining. Cell proliferation on scaffolds was assessed using MUSE™ (Merck-Millipore, Germany) cell analyser. The effect of scaffolds on osteoblast differentiation at the cellular level was evaluated by Alizarin red (AR) and alkaline phosphatase (ALP) staining. At the molecular level, the expression of osteoblast differentiation marker genes such as Runt-related transcription factor-2 (Runx2), ALP, type I collagen-1 (Col-I) and osteocalcin (OC) was determined by real-time reverse transcriptase (RT-PCR) analysis. Bone regeneration was assessed by X-ray radiographs, SEM and EDAX analyses, and histological staining such as haematoxylin and eosin staining and Masson's trichrome staining (MTS) in a rat critical-sized tibial defect model system. RESULTS: The inclusion of iron-containing Pg particles at 0.25% concentration in CS/CaPP scaffolds showed enhanced bioactivity by protein adsorption and biomineralization, compared with that shown by CS/CaPP scaffolds alone. Increased proliferation of mMSCs was observed with CS/CaPP/Pg scaffolds compared with control and CS/CaPP scaffolds. Increase in cell proliferation was accompanied by G0/G1 to G2/M phase transition with increased levels of cyclin(s) A, B and C. Pg particles in CS/CaPP scaffolds enhanced osteoblast differentiation at the cellular and molecular levels, as evidenced by increased calcium deposits, ALP activity and expression of osteoblast marker genes. In vivo implantation of scaffolds in rat critical-sized tibial defects displayed accelerated bone formation after 8 weeks. CONCLUSION: The current findings indicate that CS/CaPP scaffolds containing iron-containing Pg particles serve as an appropriate template to support proliferation and differentiation of MSCs to osteoblasts in vitro and bone formation in vivo and thus support their candidature for BTE applications.