Fabrication, characterization and osteoblast responses of poly (octanediol citrate)/bioglass nanofiber composites

Surface Modification of Titanium Implants by Metal Ions and Nanoparticles for Biomedical Application

Implant surface modification can improve osseointegration and reduce peri-implant inflammation. Implant surfaces are modified with metals because of their excellent mechanical properties and significant functions. Metal surface modification is divided into metal ions and nanoparticle surface modification. These two methods function by adding a finishing metal to the surface of the implant, and both play a role in promoting osteogenic, angiogenic, and antibacterial properties. Based on this, the nanostructural surface changes confer stronger antibacterial and cellular affinity to the implant surface. The current paper reviews the forms, mechanisms, and applications of nanoparticles and metal ion modifications to provide a foundation for the surface modification of implants.

Ceramic Nanofiber Materials for Wound Healing and Bone Regeneration: A Brief Review

Ceramic nanofibers have been shown to be a new horizon of research in the biomedical area, due to their differentiated morphology, nanoroughness, nanotopography, wettability, bioactivity, and chemical functionalization properties. Therefore, considering the impact caused by the use of these nanofibers, and the fact that there are still limited data available in the literature addressing the ceramic nanofiber application in regenerative medicine, this review article aims to gather the state-of-the-art research concerning these materials, for potential use as a biomaterial for wound healing and bone regeneration, and to analyze their characteristics when considering their application.

Bioglass incorporated methacrylated collagen bioactive ink for 3D printing of bone tissue

Bioactive 3D printed scaffolds are promising candidates for bone tissue engineering (BTE) applications. Here, we introduce a bioactive ink composed of Bioglass 45S5 (BG) and methacrylated collagen (CMA) for 3D printing of biomimetic constructs that resemble the organic and inorganic composition of native bone tissue. A uniform dispersion of BG particles within the collagen network improved stability and reduced swelling of collagen hydrogels. Rheological testing showed significant improvement in the yield stress and percent recovery of 3D printed constructs upon BG incorporation. Further, addition of BG improved the bone bioactivity of 3D printed constructs in stimulated body fluid. BG incorporated CMA (BG-CMA) constructs maintained high cell viability and enhanced alkaline phosphatase activity of human mesenchymal stem cells. In addition, cell-mediated calcium deposition was significantly higher on BG-CMA constructs, compared to CMA alone. In conclusion, 3D printed BG-CMA constructs have significant potential for use in BTE applications.

Tailoring nanocomposite interfaces with graphene to achieve high strength and toughness

The nanofiller reinforcing effect in nanocomposites is often far below the theoretically predicted values, largely because of the poor interfacial interaction between the nanofillers and matrix. Here, we report that graphene-wrapped B₄C nanowires (B₄C-NWs@graphene) empowered exceptional dispersion of nanowires in matrix and superlative nanowire-matrix bonding. The 0.2 volume % B₄C-NWs@graphene reinforced epoxy composite exhibited simultaneous enhancements in strength (144.2 MPa), elastic modulus (3.5 GPa), and ductility (15%). Tailoring the composite interfaces with graphene enabled effective utilization of the nanofillers, resulting in two times increase in load transfer efficiency. Molecular dynamics simulations unlocked the shear mixing graphene/nanowire self-assembly mechanism. This low-cost yet effective technique presents unprecedented opportunities for improving nanocomposite interfaces, enabling high load transfer efficiency, and opens up a new path for developing strong and tough nanocomposites.

Emerging themes and unifying concepts underlying cell behavior regulation by the pericellular space

Cells reside in a complex three-dimensional (3D) microenvironment where physical, chemical, and architectural features of the pericellular space regulate important cellular functions like migration, differentiation, and morphogenesis. A major goal of tissue engineering is to identify which properties of the pericellular space orchestrate these emergent cell behaviors and how. In this review, we highlight recent studies at the interface of biomaterials and single cell biophysics that are lending deeper insight towards this goal. Advanced methods have enabled the decoupling of architectural and mechanical features of the microenvironment, revealing multiple mechanisms of adhesion and mechanosensing modulation by biomaterials. Such studies are revealing important roles for pericellular space degradability, hydration, and adhesion competition in cell shape, volume, and differentiation regulation. STATEMENT OF SIGNIFICANCE: Cell fate and function are closely regulated by the local extracellular microenvironment. Advanced methods at the interface of single cell biophysics and biomaterials have shed new light on regulators of cell-pericellular space interactions by decoupling more features of the complex pericellular milieu than ever before. These findings lend deeper mechanistic insight into how biomaterials can be designed to fine-tune outcomes like differentiation, migration, and collective morphogenesis.

Gadolinium-doped bioglass scaffolds promote osteogenic differentiation of hBMSC via the Akt/GSK3β pathway and facilitate bone repair in vivo

BACKGROUND

Biomaterial-induced osteogenesis is mainly related to hierarchically porous structures and bioactive components. Rare earth elements are well known to promote osteogenesis and stimulate bone repair; however, the underlying biological effects of gadolinium (Gd) element on bone regeneration are not yet known.

METHODS

In this study, we successfully fabricated gadolinium-doped bioglass (Gd-BG) scaffolds by combining hollow mesoporous Gd-BG microspheres with chitosan and evaluated in vitro effects and underlying mechanisms with Cell Counting Kit-8, scanning electron microscopy, alkaline phosphatase, Alizarin red staining, and polymerase chain reaction. Cranial defect model of rats was constructed to evaluate their in vivo effects.

RESULTS

The results indicated that Gd-BG scaffolds could promote the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). Mechanistically, the Akt/GSK3β signaling pathway was activated by the Gd-BG scaffolds. The enhancing effect of Gd-BG scaffolds on the osteogenic differentiation of hBMSCs was inhibited by the addition of LY294002, an inhibitor of Akt. Moreover, the in vivo cranial defect model of rats indicated that the Gd-BG scaffolds could effectively promote bone regeneration.

CONCLUSION

Both in vitro and in vivo results suggested that Gd-BG scaffolds have promising applications in bone tissue engineering.

Elastomeric biocomposite of silver-containing mesoporous bioactive glass and poly(1,8-octanediol citrate): Physiochemistry and in vitro antibacterial capacity in tissue engineering applications

A novel series of silver-doped mesoporous bioactive glass/poly(1,8-octanediol citrate) (AgMBG/POC) elastomeric biocomposite scaffolds were successfully constructed by a salt-leaching technique for the first time and the effect of inclusion of different AgMBG contents (5, 10, and 20 wt%) on physicochemical and biological properties of pure POC elastomer was evaluated. Results indicated that AgMBG particles were uniformly dispersed in the POC matrix and increasing the AgMBG concentration into POC matrix up to 20 wt% enhanced thermal behaviour, mechanical properties and water uptake ability of the composite scaffolds compared to those from POC. The 20%AgMBG/POC additionally showed higher degradation rate in Tris(hydroxymethyl)-aminomethane-HCl (Tris-HCl) compared with pure POC and lost about 26% of its initial weight after soaking for 28 days. The AgMBG phase incorporation also significantly endowed the resulting composite scaffolds with efficient antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria while preserving their favorable biocompatibility with soft tissue cells (i.e., human dermal fibroblast cells). Taken together, our results suggest that the synergistic effect of both AgMBG and POC make these newly designed AgMBG/POC composite scaffold an attractive candidate for soft tissue engineering applications.

Regenerating infected bone defects with osteocompatible microspheres possessing antibacterial activity

Treatment of infected bone defects still remains a formidable clinical challenge, and the design of bone implants with both anti-bacterial activity and osteogenesis effects is nowadays regarded as a powerful strategy for infection control and bone healing.