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.
To improve the quality of life of diabetic patients, oral delivery of insulin would be better than subcutaneous injection, and the encapsulation of insulin for its oral delivery is a promising ...alternative one. In this study, we prepared an oral insulin delivery system using thiolated chitosan nanoparticles (TCNPs) loaded with insulin (Ins) and tested under in vitro and in vivo systems. TCNPs prepared from CS and pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) at 4:1 ratio showed 220 ± 4 nm, 2.3 ± 1 mV, and 119 ± 4 μmol g−1 in their size, charge and sulfhydryl content, respectively. There was a sustained release of insulin from the TCNPs at pH 5.3. TCNPs treatment did not alter cell viability in vitro and oral administration of TCNPs reached over the tip of the microvilli near the intestinal mucosa in vivo. There were increased and decreased the levels of insulin and glucose in the blood, respectively when Ins-TCNPs were orally administered in the diabetes induced rats. Thus, our results suggested that the insulin stays significantly for a prolonged period to make bio-distribution and bioavailability due to its interaction with the mucus of the intestine, thus offering a better oral insulin delivery system for diabetic patients.
•Chemical modification and characterization of thiolated chitosan nanoparticles-Insulin (TCNPs-Ins) using PETMP•Proposed the structure-activity relationship and sustained release of TCNPs-Ins at in vitro•TCNPs facilitate a prolonged residence time of orally delivered insulin in the ileum region of Wister rat by FITC conjugation.
Non-availability of an ideal alternative for autografts in treating critical-size bone defects is a major challenge in orthopedics. Phytocompounds have been proven to enhance osteogenesis via various ...osteogenic signaling pathways, but its decreased bioavailability and increased renal clearance limit its application. In this study, we designed a biocomposite scaffold comprising gelatin (Gel) and nanohydroxyapatite (nHAp) incorporated with diosmin (DM) and we investigated its bone forming potential in vitro and in vivo. Physiochemical characterization of the scaffold showed that DM had no effect on altering the material characteristics of the scaffold. The addition of DM enhanced the osteoblast differentiation potential of the scaffold in mouse mesenchymal stem cells at both cellular and molecular levels, possibly via the integrin-mediated activation of FAK and ERK signaling components. Using the rat tibial bone defective model, we identified the effect of DM in Gel/nHAp scaffold on enhancing bone formation in vivo. Based on our results, we suggest that Gel/nHAp/DM can be a potential therapeutic agent in scaffold-mediated bone regeneration.
Despite the spontaneous regenerative properties of autologous bone grafts, this technique remains dilatory and restricted to fractures and injuries. Conventional grafting strategies used to treat ...bone tissue damage have several limitations. This highlights the need for novel approaches to overcome the persisting challenges. Tissue-like constructs that can mimic natural bone structurally and functionally represent a promising strategy. Bone tissue engineering (BTE) is an approach used to develop bioengineered bone with subtle architecture. BTE utilizes biomaterials to accommodate cells and deliver signaling molecules required for bone rejuvenation. Among the various techniques available for scaffold creation, 3D-printing technology is considered to be a superior technique as it enables the design of functional scaffolds with well-defined customizable properties. Among the biomaterials obtained from natural, synthetic, or ceramic origins, naturally derived chitosan (CS) polymers are promising candidates for fabricating reliable tissue constructs. In this review, the physicochemical-biological properties and applications of CS-based 3D-printed scaffolds and their future perspectives in BTE are summarized.
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 nano‑zirconium 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.
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.
Three-dimensional (3D) printing is a promising technology to fabricate the intricate biomimetic structure. The primary focus of this study was to develop the bioactive 3D-scaffolds to enhance bone ...regeneration. The 3D-poly (lactic acid) (PLA) scaffolds were extruded based on a computer-aided design (CAD) model and coated with gelatin (Gel) containing different concentrations of mucic acid (MA) and were investigated for their osteogenic potential. Coating the PLA scaffolds with Gel/MA improved their physicochemical properties, and the addition of MA did not alter these properties. The viability of mouse mesenchymal stem cells (mMSCs, C3H10T1/2) seeded onto the PLA/Gel/MA scaffolds remained unaffected both at metabolic and cell membrane integrity levels. Alkaline phosphatase and von Kossa staining indicated the promotion of osteoblast differentiation of mMSCs by MA in the PLA/Gel scaffolds. Inclusion of MA in PLA/Gel scaffolds also increased the expression of the master bone transcription factor, Runx2, and other osteoblastic differentiation marker genes in mMSCs. Thus, our results suggested that the 3D-printed PLA scaffolds coated with Gel/MA favor osteoblast differentiation and have potential applications in bone tissue engineering.
Display omitted
•Fabrication of trans-Anethole loaded PCL/PVP fibers by electrospinning technique.•Characterization by physiochemical, material and biological studies.•Induction of osteogenesis by ...trans-Anethole.•Regulation of Runx2 co-activators by trans-Anethole promoting bone regeneration.
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.
•The bioavailability and osteogenic effects of chrysin, a natural flavonoid, were investigated.•Chrysin was incorporated at different concentrations into biocomposite scaffolds.•Chrysin-containing ...scaffolds were not cytotoxic to mouse mesenchymal stem cells.•Chrysin released from scaffolds stimulated cell proliferation.•Chrysin released from scaffolds promoted osteoblast differentiation.
Numerous phytochemical compounds have recently been reported to stimulate osteogenesis. In this study, the bioavailability and osteogenic effects of chrysin, a natural flavonoid, were investigated. Chrysin was incorporated at different concentrations into biocomposite scaffolds containing carboxymethyl cellulose, chitosan, and nano-hydroxyapatite, through the freeze-drying method. The physicochemical and material characteristics of chrysin-incorporated scaffolds were investigated, and chrysin had no effect on them. These chrysin-containing scaffolds were not cytotoxic to mouse mesenchymal stem cells (mMSCs). Chrysin released from scaffolds stimulated cell proliferation and promoted osteoblast differentiation. Osteoblast differentiation enhanced by chrysin from scaffolds could be due to downregulation of co-repressors of the osteoblast differentiation transcription factor Runx2 in these cells. Thus, chrysin release from scaffolds has potential effects on proliferation and differentiation of mMSCs; hence, it has potential application in bone tissue engineering.
Spontaneous bone regeneration is heavily restricted because of bone defects, and external mediation is required to enhance repair and regeneration. Bone tissue engineering (BTE) is a ...multidisciplinary field that offers promising substitutes to traditional methods—namely, autografts, allografts, and xenografts. Amidst the various scaffolds for BTE applications, it has been demonstrated that hydrogels are promising templates for bone regeneration owing to their similarities to the natural extracellular matrix. Regardless of the development of a variety of biomaterials, chitosan (CS) as a natural biopolymer has drawn tremendous attention in recent years for its use as a valuable graft material to form thermo/pH-responsive injectable hydrogels. Formulations of CS-based injectable hydrogels are advantageous in terms of their high-water imbibing capability, minimal invasiveness, porous networks, and ability to mold perfectly into an irregular defect. In this review, the physicochemical properties and applications of thermo/pH-responsive CS-based hydrogels and their future perspectives in BTE are briefly outlined.
•Bone tissue engineering offers promising substitutes to traditional methods.•Hydrogels are promising templates for bone regeneration.•Chitosan (CS) as a graft material forms thermo/pH-responsive injectable hydrogels.•The physicochemical properties and applications of these hydrogels are outlined.
PDF
