Studies on effect of CuO addition on mechanical properties and in vitro cytocompatibility in 1393 bioactive glass scaffold

Copper ions-photo dual-crosslinked alginate hydrogel for angiogenesis and osteogenesis

Early healing of bone defects is still a clinical challenge. Many bone-filling materials have been studied, among which photocrosslinked alginate has received significant attention due to its good biocompatibility and morphological plasticity. Although it has been confirmed that photocrosslinked alginate can be used as an extracellular matrix for 3D cell culture, it lacks osteogenesis-related biological functions. This study constructed a copper ions-photo dual-crosslinked alginate hydrogel scaffold by controlling the copper ion concentration. The scaffolds were shaped by photocrosslinking and then endowed with biological functions by copper ions crosslinking. According to in vitro research, the dual-crosslinked hydrogel increased the compressive strength and favored copper dose-dependent osteoblast differentiation and cell surface adherence of rat bone marrow mesenchymal stem cells and the expression of type I collagen (Col1), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), vascular endothelial growth factor (VEGF). In addition, hydrogel scaffolds were implanted into rat skull defects, and more angiogenesis and osteogenesis could be observed in in vivo studies. The above results show that the copper-photo-crosslinked hydrogel scaffold has excellent osseointegration properties and can potentially promote angiogenesis and early healing of bone defects, providing a reference solution for bone tissue engineering materials.

Promoting Angiogenesis/Osteogenesis by a New Copper/Magnesium Hydroxide Hybrid Nanoparticle: In Vitro and In Vivo Investigation

In this study, a new hybrid nanoparticle composed of magnesium hydroxide and copper oxide (Mg(OH)2/CuO) with an optimized ratio of magnesium (Mg) to copper (Cu) was designed and incorporated into a 3D-printed scaffold made of polycaprolactone (PCL) and gelatin. These hybrid nanostructures (MCNs) were prepared using a green, solvent-free method. Their topography, surface morphology, and structural properties were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The fabricated 3D-printed PCL/Gelatin/MCN scaffolds were investigated in vitro and in vivo. Cell viability tests on murine calvarial preosteoblasts (MC3T3-E1) and human umbilical vein endothelial cells (HUVECs) demonstrated that the scaffolds could induce proper cell proliferation. Additionally, the angiogenic and osteogenic properties of the constructs were evaluated using alkaline phosphatase (ALP) activity, osteogenesis-related, and angiogenesis-related gene expression tests. The in vivo study was conducted using a rat calvarial defect model, which confirmed the superior angiogenic and osteogenic properties of the PCL/gelatin/MCN scaffolds compared to PCL/Gelatin and PCL/Gelatin/Mg(OH)2 scaffolds. Overall, the PCL/Gelatin/MCN scaffolds showed promising potential for bone regeneration, particularly for critical-sized defects where proper angiogenesis is essential for tissue reconstruction.

Copper nanoparticles loaded gelatin/ polyvinyl alcohol/ guar gum-based 3D printable multimaterial hydrogel for tissue engineering applications

Hydrogels are becoming increasingly significant in tissue engineering because of their numerous benefits, including biocompatibility, biodegradability, and their ability to provide a supportive structure for cell proliferation. This study presents the synthesis and characterization of a new multimaterial hydrogel with 3D-printing capabilities composed of copper nanoparticle-reinforced gelatin, polyvinyl alcohol (PVA), and guar gum-based biomaterials intended for tissue engineering applications. Combining CuNPs aims to enhance the hydrogel's antibacterial properties, mechanical strength, and bioactivity, which are essential for successful tissue regeneration. Hydrogels are chemically cross-linked with glyoxal and analyzed through different assessments to examine the compressive behavior, surface morphology, sorbing capacity, biocompatibility, thermal stability, and degradation properties. The results demonstrated that including CuNPs significantly improved the hydrogel's compressive modulus (4.18 MPa) for the hydrogel with the CuNPs and provided better antibacterial activity against common pathogens with controlled degradation. All the hydrogels exhibited a lower coefficient of friction, which was below 0.1. In vitro cell culture studies using chondrocytes indicated that the CuNPs-loaded hydrogel supported cell proliferation and growth of chondrogenic genes such as collagen type II (COL2) and aggrecan (ACAN). The biocompatibility and enhanced mechanical properties of the multimaterial hydrogel make it a promising candidate for developing customized, patient-specific tissue engineering scaffolds.

In vitro cytotoxicity of magnetic-fluorescent bioactive glasses on SaOS-2, MC3T3-E1, BJ fibroblast cells, their hemolytic activity, and sorafenib release behavior

In the study, the fabrication of superparamagnetic-fluorescent bioactive glasses in the form of the particle, nanofiber, and 3D scaffolds was performed by including maghemite (γ-Fe2O3) nanoparticles and photoluminescent rare earth element ions (Eu3+, Gd3+, and Yb3+) using sol-gel, electrospinning, and robocasting techniques, respectively. The in vitro cytotoxicity of the magnetic-fluorescent bioactive glasses on osteosarcoma SaOS-2, pre-osteoblast MC3T3-E1, and BJ fibroblast cells, as well as their hemolytic activity and sorafenib tosylate loading and release behavior, were investigated. The cytotoxicity of the bioactive glass samples was tested using the MTT assay. Additionally, the alkaline phosphatase activity of the studied glasses was examined as a function of time. The mineralization behavior of the pre-osteoblast cell-seeded glass samples was analyzed using Alizarin red S staining. Results revealed that the in vitro cytotoxicity of the studied bioactive glasses in the form of particles and nanofibers depended on the sample concentration, whereas in the case of the 3D scaffolds, no cytotoxic response was observed on the osteosarcoma, pre-osteoblast, and fibroblast cells. Similarly, particle and nanofiber-based glass samples induced dose-dependent hemolysis on red blood cells. Drug loading rates were much lower for the 3D scaffolds compared to the particle and nanofiber-based samples. Drug release rates ranged from 25 % to 90 %, depending on the bioactive glass morphology and the pH of the release medium. It was concluded that the studied bioactive glasses have the potential to be used in tissue engineering applications and cancer therapy.

Advancements in drug-loaded hydrogel systems for bone defect repair

Bone defects are primarily the result of high-energy trauma, pathological fractures, bone tumor resection, or infection debridement. The treatment of bone defects remains a huge clinical challenge. The current treatment options for bone defects include bone traction, autologous/allogeneic bone transplantation, gene therapy, and bone tissue engineering amongst others. With recent developments in the field, composite scaffolds prepared using tissue engineering techniques to repair bone defects are used more often. Among the various composite scaffolds, hydrogel exhibits the advantages of good biocompatibility, high water content, and degradability. Its three-dimensional structure is similar to that of the extracellular matrix, and as such it is possible to load stem cells, growth factors, metal ions, and small molecule drugs upon these scaffolds. Therefore, the hydrogel-loaded drug system has great potential in bone defect repair. This review summarizes the various natural and synthetic materials used in the preparation of hydrogels, in addition to the latest research status of hydrogel-loaded drug systems.

Poly(ε-caprolactone)/bioactive glass composite electrospun fibers for tissue engineering applications

In this work, composite electrospun fibers containing innovative bioactive glass nanoparticles were produced and characterized. Poly(ε-caprolactone), benign solvents, and sol-gel B- and Cu-doped bioactive glass powders were used to fabricate fibrous scaffolds. The retention of bioactive glass nanoparticles in the polymer matrix, the electrospinnability of this novel solution and the obtained electrospun composites were extensively characterized. As a result, composite electrospun fibers characterized by biocompatibility, bioactivity, and exhibiting overall properties adequate for both hard and soft tissue engineering applications, have been produced. The addition of these bioactive glass nanoparticles was, indeed, able to impart bioactive properties to the fibers. Cell culture studies show promising results, demonstrating proliferation and growth of cells on the composite fibers. Wettability, degradation rate, and mechanical performance were also tested and are in line with previous results.

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

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.

Bioactive ZnO-assisted 1393 glass scaffold promotes osteogenic differentiation: Some studies

We developed ZnO-assisted 1393 bioactive glass-based scaffold with suitable mechanical properties through foam replica technique and observed to be suitable for bone tissue engineering application. However, the developed scaffolds' ability to facilitate cellular infiltration and integration was further assessed through in vivo studies in suitable animal model. Herein, the pure 1393 bioactive glass (BG) and ZnO-assisted 1393 bioactive glass- (ZnBGs; 1, 2, 4 mol% ZnO substitution for SiO₂ in pure BG is named as Z1BG, Z2BG, Z3BG, respectively) based scaffolds were prepared through sol-gel route, followed by foam replica techniques and characterized by a series of in vitro and some in vivo tests. Different cell lines like normal mouse embryonic cells (NIH/3T3), mouse bone marrow stromal cells (mBMSc), peripheral blood mononuclear cells, that is, lymphocytes and monocytes (PBMC) and U2OS (carcinogenic human osteosarcoma cells) were used in determination and comparative analysis of the biological compatibility of the BG and ZnBGs. Also, the alkaline phosphatase (ALP) activity, and osteogenic gene expression by primer-specific osteopontin (OPN), osteocalcin (OCN), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were performed to study osteogenic differentiability of the stromal cells in different BGs. Moreover, radiological and histopathological tests were performed in bone defect model of Wister rats to evaluate the in vivo bone regeneration and healing. Interestingly, these studies demonstrate augmented biological compatibility, and superior osteogenic differentiation in ZnBGs, in particular Z3BG than the pure BG in most cases.

The role of copper chromite nanoparticles on physical and bio properties of scaffolds based on poly(glycerol-azelaic acid) for application in tissue engineering fields

Tissue engineering combines suitable cells, engineering methods, and proper biochemical factors to develop functional and biological tissues and repair damaged tissues. In this study, we focused on synthesizing and characterizing a nanocomposite scaffold based on glycerol and azelaic acid (Gl-Az) combined with copper chromite (CuCr₂O₄) nanoparticles in order to increase the osteogenic differentiation efficiency of human adipose-derived stem cells (hADSCs) on fabricated scaffolds. The degradability and hydrophobicity properties as well as mechanical and thermal behaviors of nanocomposite scaffolds were investigated. Next, the cell toxicity of glycerol, azelaic acid and CuCr₂O₄ nanoparticles was studied by MTT assay test and acridine orange staining. Finally, the osteogenic differentiation of hADSCs on Gl-Az-CuCr₂O₄ scaffolds was examined using alkaline phosphatase activity (ALP) and calcium content. The obtained results demonstrated that Gl-Az-1%CuCr₂O₄ not only showed appropriate mechanical strength, biocompatibility and degradability but also influenced the capability of hADSCs to differentiate into osteogenic lineages. The hADSCs culture in Gl-Az-1%CuCr₂O₄ showed a significant increase in ALP activity levels and calcium biomineralization after 14 days of osteogenic differentiation. In conclusion, the Gl-Az-1%CuCr₂O₄ nanocomposite could be used as a biocompatible and degradable scaffold to induce the bone differentiation of hADSCs and it could be a promising scaffold in bone regenerative medicine.

Enhanced osteoarthritis therapy by nanoengineered mesenchymal stem cells using biomimetic CuS nanoparticles loaded with plasmid DNA encoding TGF-β1

Mesenchymal stem cells (MSCs) therapy shows the potential benefits to relieve clinical symptoms of osteoarthritis (OA), but it is uncertain if it can repair articular cartilage lesions — the main pathology of OA. Here, we prepared biomimetic cupper sulfide@phosphatidylcholine (CuS@PC) nanoparticles (NPs) loaded with plasmid DNA (pDNA) encoding transforming growth factor-beta 1 (TGF-β1) to engineer MSCs for enhanced OA therapy via cartilage regeneration. We found that the NPs not only promoted cell proliferation and migration, but also presented a higher pDNA transfection efficiency relative to commercial transfection reagent lipofectamine 3000. The resultant CuS/TGF-β1@PC NP-engineered MSCs (termed CTP-MSCs) were better than pure MSCs in terms of chondrogenic gene expression, glycosaminoglycan deposition and type II collagen formation, favoring cartilage repair. Further, CTP-MSCs inhibited extracellular matrix degradation in interleukin-1β-induced chondrocytes. Consequently, intraarticular administration of CTP-MSCs significantly enhanced the repair of damaged cartilage, whereas pure MSCs exhibited very limited effects on cartilage regeneration in destabilization of the medial meniscus (DMM) surgical instability mice. Hence, this work provides a new strategy to overcome the limitation of current stem cell therapy in OA treatment through developing more effective nanoengineered MSCs.

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Biomimetic CuS nanoparticles (NPs) loaded with TGF-β1 pDNA are prepared for nanoengineering of MSCs.

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CuS/TGF-β1@PC NPs are more efficient than commercial transfection agent in terms of pDNA transfection.

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The NP-engineered CTP-MSCs exhibit enhanced migration, chondrogenesis and inhibition of ECM degradation.

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CTP-MSCs effectively treat osteoarthritis (OA) mice models via cartilage regeneration.

A Review on Three-Dimensional Printed Silicate-Based Bioactive Glass/Biodegradable Medical Synthetic Polymer Composite Scaffolds

In recent years, tissue engineering scaffolds have turned into the preferred option for the clinical treatment of pathological and traumatic bone defects. In this field, silicate-based bioactive glasses (SBGs) and biodegradable medical synthetic polymers (BMSPs) have attracted a great deal of attention owing to their shared exceptional advantages, like excellent biocompatibility, good biodegradability, and outstanding osteogenesis. Three-dimensional (3D) printed SBG/BMSP scaffolds can not only replicate the mechanical properties and microstructure of natural bone but also degrade in situ after service and end up being replaced by regenerated bone tissue in vivo. This review first consolidates the research efforts in 3D printed SBG/BMSP scaffolds, and then focuses on their composite mechanism. This review may help to provide a fresh perspective for SBG/BMSP composite system in bone regeneration.

Poly(Glycerol Succinate) as Coating Material for 1393 Bioactive Glass Porous Scaffolds for Tissue Engineering Applications

BACKGROUND

Aliphatic polyesters are widely used for biomedical, pharmaceutical and environmental applications due to their high biodegradability and cost-effective production. Recently, star and hyperbranched polyesters based on glycerol and ω-carboxy fatty diacids have gained considerable interest. Succinic acid and bio-based diacids similar to glycerol are regarded as safe materials according to the US Food and Drug Administration (FDA). Bioactive glass scaffolds utilized in bone tissue engineering are relatively brittle materials. However, their mechanical properties can be improved by using polymer coatings that can further control their degradation rate, tailor their biocompatibility and enhance their performance. The purpose of this study is to explore a new biopolyester poly(glycerol succinate) (PGSuc) reinforced with mesoporous bioactive nanoparticles (MSNs) as a novel coating material to produce hybrid scaffolds for bone tissue engineering.

METHODS

Bioactive glass scaffolds were coated with neat PGSuc, PGSuc loaded with dexamethasone sodium phosphate (DexSP) and PGSuc loaded with DexSP-laden MSNs. The physicochemical, mechanical and biological properties of the scaffolds were also evaluated.

RESULTS

Preliminary data are provided showing that polymer coatings with and without MSNs improved the physicochemical properties of the 1393 bioactive glass scaffolds and increased the ALP activity and alizarin red staining, suggesting osteogenic differentiation potential when cultured with adipose-derived mesenchymal stem cells.

CONCLUSIONS

PGSuc with incorporated MSNs coated onto 1393 bioactive glass scaffolds could be promising candidates in bone tissue engineering applications.

Engineered Cu-PEN Composites at the Nanoscale: Preparation and Characterisation

As polymeric materials are already used in many industries, the range of their applications is constantly expanding. Therefore, their preparation procedures and the resulting properties require considerable attention. In this work, we designed the surface of polyethylene naphthalate (PEN) introducing copper nanowires. The surface of PEN was transformed into coherent ripple patterns by treatment with a KrF excimer laser. Then, Cu deposition onto nanostructured surfaces by a vacuum evaporation technique was accomplished, giving rise to nanowires. The morphology of the prepared structures was investigated by atomic force microscopy and scanning electron microscopy. Energy dispersive spectroscopy and X-ray photoelectron spectroscopy revealed the distribution of Cu in the nanowires and their gradual oxidation. The optical properties of the Cu nanowires were measured by UV-Vis spectroscopy. The sessile drop method revealed the hydrophobic character of the Cu/PEN surface, which is important for further studies of biological responses. Our study suggests that a combination of laser surface texturing and vacuum evaporation can be an effective and simple method for the preparation of a Cu/polymer nanocomposite with potential exploitation in bioapplications; however, it should be borne in mind that significant post-deposition oxidation of the Cu nanowire occurs, which may open up new strategies for further biological applications.

Bioactive Bilayer Glass Coating on Porous Titanium Substrates with Enhanced Biofunctional and Tribomechanical Behavior

The use of porous titanium samples fabricated by space-holder powder metallurgy with bioactive coatings has already been reported to prevent resorption of the bone surrounding the implant and improve osseointegration, respectively. However, the presence of pores as well as the poor adherence and the brittle behavior inherent to glassy coatings affect the service behavior of implants fabricated from these samples. Therefore, they need to be optimized. In this work, 50 vol.% of porosity titanium substrates were manufactured with different pore range size (100–200 and 355–500 µm) spacer particles and coated with a bilayer of bioactive glasses (45S5/1393). The effect of the pores on the tribomechanical properties and infiltration of the bioactive glass 1393 along with the bioactivity of the bioactive glass 45S5 were evaluated by instrumented micro-indentation and scratch tests and the formation of hydroxyapatite in simulated body fluid. The results obtained were very promising as potential implants for the replacement of small tumors in cortical bone tissues, mainly due to the smaller pores that present an improved biomechanical and biofunctional balance.

Copper-based biomaterials for bone and cartilage tissue engineering

BACKGROUD

Tissue engineering using cells, scaffolds, and bioactive molecules can promote the repair and regeneration of injured tissues. Copper is an essential element for the human body that is involved in many physiological activities and in recent years, copper has been used increasingly in tissue engineering.

METHODS

The current advances of copper-based biomaterial for bone and cartilage tissue engineering were searched on PubMed and Web of Science.

RESULTS

Various forms of copper-based biomaterials, including pure copper, copper ions, copper nanoparticles, copper oxides, and copper alloy are introduced. The incorporation of copper into base materials provides unique properties, resulting in tuneable porosity, mechanical strength, degradation, and crosslinking of scaffolds. Copper also shows promising biological performance in cell migration, cell adhesion, osteogenesis, chondrogenesis, angiogenesis, and antibacterial activities. In vivo applications of copper for bone and cartilage tissue engineering are discussed.

CONCLUSION

This review focuses on copper's physiochemical and biological effects, and its applications in bone and cartilage tissue engineering. The potential limitations and future perspectives are also discussed.

TRANSLATIONAL POTENTIAL OF THIS ARTICLE

This review introduces the recent advances in copper-based biomaterial for bone and cartilage tissue engineering. This revie could guide researchers to apply copper in biomaterials, improving the generation of bone and cartilages, decrease the possibility of infection and shorten the recovery time so as to decrease medical costs.

CuO assisted borate 1393B3 glass scaffold with enhanced mechanical performance and cytocompatibility: An In vitro study

Herein, three dimensional porous 1393B3 borate-based glass (BBG) scaffold along with their CuO derivatives (C1BBG, C2BBG, and C3BBG) tailored with trabecular bones' architecture were prepared by melt-quench route followed by foam replica technique. The properties of 'CuO incorporated' scaffolds, as compared to 'as prepared' scaffold were analyzed by a series of In vitro investigations for enhancement in biological compatibility, bioactivity, and physicomechanical performances. The in vitro study demonstrates superior mechanochemical stability of CBBGs (CuO derived 1393B3) than the pure BBG, while causing no or minimal effect on bioactivity and cytocompatibility post CuO incorporation to the BBG. In fact, the biological compatibility examined through MTT, Live/Dead, and cell adhesion study using the L929 cell lines was enhanced in the CBBGs up to 1% CuO incorporated scaffolds (C1BBG and C2BBG) in most cases. However, the enhanced biological compatibility was observed in C1BBG in comparison to other BBGs. Thus, the CuO incorporation into BBG enhanced mechanochemical and biological performance without affecting the bioactivity of the scaffold; henceforth, CBBGs could be considered neo bone tissue regenerative biomaterials.

On the role of alginate coating on the mechanical and biological properties of 58S bioactive glass scaffolds

In this study, novel 3D porous alginate-coated 58S bioactive glass scaffolds were fabricated through a foam replication method using a combination of amorphous 58S bioactive glass structure and sodium alginate. The formation of the alginate coating on the surface of the struts of BG scaffolds was confirmed. The effect of alginate coating on the microstructure, mechanical properties, biodegradability, biomineralization, adhesion, viability, and differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) on the 58S BG scaffolds were evaluated. A 45.2% increase in hMSC's viability and a 3.4-fold increase in ALP activity of the 1AlBG scaffold in the absence of an osteogenic differentiation media compared to an uncoated BG scaffold were observed. Notably, gene expression analysis exhibited that the 1AlBG scaffold resulted in accelerated osteogenic differentiation of hMSCs, as expression of COL-1, RUNX2, and OCN increased after 14 days. Results revealed a significant increase of antibacterial inhibition in the 1AlBG scaffold in comparison to the BG scaffold. Based on the microstructural, mechanical, and biological investigations, the 1AlBG scaffold exhibited enhanced mechanical and biological properties, making it a promising candidate for bone regeneration. Overall, our findings have highlighted the potential of alginate-coated BG scaffolds to stimulate bone regeneration through stem cell osteoinduction.

Biofunctional and Tribomechanical Behavior of Porous Titanium Substrates Coated with a Bioactive Glass Bilayer (45S5-1393)

The porous substrates of commercially pure titanium have been coated with a novel bilayer of bioactive glasses (BGs), 45S5 and 1393, to improve the osseointegration and solve the stress-shielding phenomenon of titanium partial implants. The porosity of the substrates and the scratch resistance and bioactivity of the coating have been evaluated. Results are discussed in terms of stiffness and yield strength of the substrates, as well as the chemical composition, thickness, and design of the bioglass coating (monolithic vs bilayer). The role of the pores was a crucial issue in the anchoring of the coating, both in porosity percentage (30 and 60 vol %) and in pore range size (100-200 and 355-500 μm). The study was focused on the adhesion and infiltration of a 1393 bioglass layer (in contact with a porous titanium substrate), in combination with the biofunctionality of the 45S5 bioglass layer (surrounded by the host bone tissue), as 1393 bioglass enhances the adherence, while 45S5 bioglass promotes higher bioactivity. This bioactivity of the raw powder was initially estimated by nuclear magnetic resonance, through the evaluation of the chemical environments, and confirmed by the formation of hydroxyapatite when immersed in a simulated body fluid. The results revealed that the substrate with 30 vol % of porosity and a range of 355-500 μm pore size, coated with this novel BG bilayer, presented the best combination in terms of mechanical and biofunctional properties.

Cu, Zn doped borate bioactive glasses: antibacterial efficacy and dose-dependent in vitro modulation of murine dendritic cells

Among emerging biomaterials, bioactive glasses (BGs) are being widely explored for various applications in tissue engineering. However, the effects of BGs (in particular BG ionic dissolution products) on immune cells and specifically on dendritic cells (DCs), which are the most potent antigen-presenting cells of the immune system, have not been previously investigated in detail. Such interactions between BGs and DCs must be assessed as a novel biocompatibility criterion for biomaterials, since, with the increased application possibilities of BGs, the modulation of the immune system may induce potential complications and undesired side effects. Indeed, the effects of BG exposure on specific immune cells are not well understood. Thus, in this study we investigated, for the first time, the effect of borate BGs doped with biologically active ions on specific immune cells, such as DCs and we further investigated the antibacterial properties of these borate BGs. The compositions of the borate BGs (B3) were based on the well-known 13-93 (silicate) composition by replacing silica with boron trioxide and by adding copper (3 wt%) and/or zinc (1 wt%). By performing an agar diffusion test, the antibacterial effect depending on the compositions of the borate BGs could be proved. Furthermore we found a dose-dependent immune modulation of DCs after treatment with borate BGs, especially when the borate BGs contained Zn and/or Cu. Depending on the ion concentration and the rise in pH, the phenotype and function of DCs were modified. While at low doses B3 and Zn-doped B3 BGs had no impact on DC viability, Cu containing BGs strongly affected cell viability. Furthermore, the surface expression of DC-specific activation markers, such as the major histocompatibility complex (MHC)-II, CD86 and CD80, was modulated. In addition, also DC mediated T-cell proliferation was remarkably reduced when treated with high doses of B3-Cu and B3-Cu-Zn BGs. Interestingly, the release of inflammatory cytokines increased after incubation with B3 and B3-Zn BGs compared to mock-treated DCs. Considering the essential role of DCs in the modulation and regulation of immune responses, these findings provide first evidence of phenotypic and functional consequences regarding the exposure of DCs to BGs in vitro.

Fabrication and evaluation of non-mulberry silk fibroin fiber reinforced chitosan based porous composite scaffold for cartilage tissue engineering

Lack of potential regenerative medicine to reconstruct damaged cartilage tissue has accelerated investigation and development of potential biomaterial for cartilage tissue engineering. In this study, we fabricated micron-sized non-mulberry silk fibroin fiber (SFF) using N,N-Dimethylacetamide (DMA_C)/10% LiBr solution and further used to develop SFF reinforced chitosan(CH) based porous scaffold with desired pore size, porosity, swelling and structural stability. The developed scaffold was characterized for its various physico-chemical, mechanical and biological properties. The developed CH/SFF composite scaffold facilitates human mesenchymal stem cell (hMSCs) attachment, colonization and extracellular matrix deposition. Furthermore, hMSCs shows significantly higher sulfated glycosaminoglycan deposition over CH/SFF in comparison to pure chitosan scaffold (control). Immunocytochemistry studies have shown enhanced expression of collagen type II and aggrecan by hMSCs over composite scaffold than chitosan scaffold. Thus, non-mulberry silk fibroin fiber reinforced chitosan based scaffold might be suitable scaffold that can act as a potential artificial matrix for cartilage tissue engineering.