Biomimetic Nylon 6-Baghdadite Nanocomposite Scaffold for Bone Tissue Engineering

3D printed polylactic acid/polyethylene glycol/bredigite nanocomposite scaffold enhances bone tissue regeneration via promoting osteogenesis and angiogenesis

Recently, the fabrication of personalized scaffolds with high accuracy has been developed through 3D printing technology. In the current study, polylactic acid/polyethylene glycol (PLA/PEG) composite scaffolds with varied weight percentages (0, 5, 10, 20 and 30 %) of bredigite nanoparticles (B) were fabricated using the 3D printing and then characterized through scanning electron microscopy and Fourier transform infra-red spectroscopy. The addition of B nanoparticles up to 20 wt% to PLA/PEG scaffold increased the compressive strength (from 7.59 to 13.84 MPa) and elastic modulus (from 142.42 to 268.33 MPa). The apatite formation ability as well as inorganic ion release in simulated body fluid were investigated for 28 days. The MG-63 cells viability and adhesion were enhanced by increasing the amount of B in the PLA/PEG scaffold and the osteogenic differentiation of the rat bone marrow mesenchymal stem cells was confirmed by alkaline phosphatase activity test and alizarin red staining. According to chorioallantoic membrane assay, the highest angiogenesis occurred around the PLA/PEG/B30 scaffold. In vivo experiments on a rat calvarial defect model demonstrated an almost complete recovery in the PLA/PEG/B30 group within 8 weeks. Based on the results, the PLA/PEG/B30 composite scaffold is proposed as an optimal scaffold to repair bone defects.

Evaluation of baghdadite (Ca3ZrSi2O9) cements for the application as novel endodontic filling materials

OBJECTIVES

Baghdadite (Ca3ZrSi2O9) cements of various composition have been investigated in this study regarding an application as endodontic filling materials.

METHODS

Cements were either obtained by mixing mechanically activated baghdadite powder with water (maBag) or by subsequently substituting the ß-tricalcium phosphate (ß-TCP) component in a brushite forming calcium phosphate cement. The cements were analyzed for their mechanical performance, injectability, radiopacity, phase composition and antimicrobial properties.

RESULTS

The cements demonstrated sufficient mechanical performance with a compressive strength of ∼1 MPa (maBag) and 2.3 - 17.4 MPa (substituted calcium phosphate cement), good injectability > 80 % depending on the powder to liquid ratio and an intrinsic radiopacity of 1.13 - 2.05 mm aluminum equivalent. Immersion in artificial saliva proved their bioactivity by the formation of calcium phosphate and calcium silicate precipitates on the cement surface. The bacterial activity of Staphylococcus aureus cultured on the surface of the cements was found to be similar compared to clinical standard ProRoot MTA cement or even reduced by a factor of 3 for Streptococcus mutans.

SIGNIFICANCE

In combination with their antibacterial properties, baghdadite cements are thought to have the potential to fulfil the clinical requirements for endodontic filling materials.

Melatonin-loaded mesoporous zinc- and gallium-doped hydroxyapatite nanoparticles to control infection and bone repair

Effective treatment of infected bone defects resulting from multi-drug resistant bacteria (MDR) has emerged as a significant clinical challenge, highlighting the pressing demand for potent antibacterial bone graft substitutes. Mesoporous nanoparticles have been introduced as a promising class of biomaterials offering significant properties for treating bone infections. Herein, we synthesize antibacterial mesoporous hydroxyapatite substituted with zinc and gallium (Zn-Ga:mHA) nanoparticles using a facile sol-gel method. The resulting mesoporous nanoparticles are applied for the controlled release of melatonin (Mel). Zn-Ga:mHA nanoparticles with an average particle size of 36 ± 3 nm and pore size of 10.6 ± 0.4 nm reveal a Mel loading efficiency of 58 ± 1%. Results show that 50% of Mel is released within 20 h and its long-term release is recorded up to 50 h. The Zn-Ga:mHA nanoparticles exhibit highly effective antibacterial performance as reflected by a 19 ± 1% and 8 ± 2% viability reduction in Escherichia coli and Staphylococcus bacteria, respectively. Noticeably, Mel-loaded Zn-Ga:mHA nanoparticles are also cytocompatible and stimulate in vitro osteogenic differentiation of human mesenchymal stem cells (hMSCs) without any osteoinductive factor. In vivo studies in a rabbit skull also show significant regeneration of bone during 14 days. In summary, Mel-loaded Zn-Ga:mHA nanoparticles provide great potential as an antibacterial and osteogenic component in bone substitutes like hydrogels, scaffolds, and coatings.

3D printing technology and its combination with nanotechnology in bone tissue engineering

With the graying of the world's population, the morbidity of age-related chronic degenerative bone diseases, such as osteoporosis and osteoarthritis, is increasing yearly, leading to an increased risk of bone defects, while current treatment methods face many problems, such as shortage of grafts and an incomplete repair. Therefore, bone tissue engineering offers an alternative solution for regenerating and repairing bone tissues by constructing bioactive scaffolds with porous structures that provide mechanical support to damaged bone tissue while promoting angiogenesis and cell adhesion, proliferation, and activity. 3D printing technology has become the primary scaffold manufacturing method due to its ability to precisely control the internal pore structure and complex spatial shape of bone scaffolds. In contrast, the fast development of nanotechnology has provided more possibilities for the internal structure and biological function of scaffolds. This review focuses on the application of 3D printing technology in bone tissue engineering and nanotechnology in the field of bone tissue regeneration and repair, and explores the prospects for the integration of the two technologies.

Incorporation of graphene oxide as a coupling agent in a 3D printed polylactic acid/hardystonite nanocomposite scaffold for bone tissue regeneration applications

3D printing fabrication has become a dominant approach for the creation of tissue engineering constructs as it is accurate, fast, reproducible and can produce patient-specific templates. In this study, 3D printing is applied to create nanocomposite scaffold of polylactic acid (PLA)/hardystonite (HT)-graphene oxide (GO). GO is utilized as a coupling agent of alkaline treated HT nanoparticles within PLA matrix. The addition of HT-GO nanoparticles of up to 30 wt% to PLA matrix was found to increase the degradability from 7.33 ± 0.66 to 16.03 ± 1.47 % during 28 days. Also, the addition of 20 wt% of HT-GO nanoparticles to PLA scaffold (PLA/20HTGO sample) significantly increased the compressive strength (from 7.65 ± 0.86 to 14.66 ± 1.01 MPa) and elastic modulus (from 94.46 ± 18.03 to 189.15 ± 10.87 MPa). The apatite formation on the surface of nanocomposite scaffolds in simulated body fluid within 28 days confirmed the excellent bioactivity of nanocomposite scaffolds. The MG63 cell adhesion and proliferation and, also, the rat bone marrow mesenchymal stem cells osteogenic differentiation were highly stimulated on the PLA/20HTGO scaffold. According to the sum of results obtained in the current study, the optimized PLA/20HTGO nanocomposite scaffold is highly promising for hard tissue engineering applications.

Novel barium-doped-baghdadite incorporated PHBV-PCL composite fibrous scaffolds for bone tissue engineering

Bioceramic/polymer composites have dragged a lot of attention for treating hard tissue damage in recent years. In this study, we synthesized barium-doped baghdadite (Ba-BAG), as a novel bioceramic, and later developed fibrous composite poly (hydroxybutyrate) co (hydroxyvalerate)- polycaprolactone (PHBV-PCL) scaffolds containing different amounts of baghdadite (BAG) and Ba-BAG, intended to be used in bone regeneration. Our results demonstrated that BAG and Ba-doped BAG powders were synthesized successfully using the sol-gel method and their microstructural, physicochemical, and cytotoxical properties results were evaluated. In the following, PHBV/PCL composite scaffolds containing different amounts of BAG and Ba-BAG (1, 3, and 5 wt%) were produced by the wet electrospinning method. The porosity of scaffolds decreased from 78% to 72% in Ba-BAG-incorporated PHBV/PCL scaffolds. The compressive strength of the scaffolds was between 4.69 and 9.28 kPa, which was increased to their maximum values in the scaffolds with Ba-BAG. The presence of BAG and Ba-BAG in the polymer scaffolds resulted in increasing bioactivity, and it was introduced as a suitable way to control the degradation rate of scaffolds. The presence of the BAG component was a major reason for higher cell proliferation in reinforced PHBV/PCL polymeric scaffolds, while Ba existence played its influential role in the higher osteogenic activity of cells on Ba-BAG incorporated PHBV/PCL scaffolds. Thus, the incorporation of Ba-BAG bioceramic materials into the structure of polymeric PHBV/PCL scaffolds promoted their various properties, and allow these scaffolds to be used as promising candidates in bone tissue engineering applications.

Preparation of Bioactive Polyamide Fibres Modified with Acetanilide and Copper Sulphate

This paper presents a simple method of obtaining polyamide 6 fibres modified with acetanilide and copper ions. During the spinning of the fibres with the additives applied, a partial reduction of CuSO4 to Cu2+ and Cu+ ions occurs, which is observed as a change in the blue colour of the prepared polyamide granulate to the grey-brown colour of the formed fibres. CuMPs obtained as a result of the salt reduction should give the obtained fibres bioactive properties. Three types of microorganisms were selected to assess the microbiological activity of the obtained fibres, i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. The fibres have antibacterial activity against Gram-positive and Gram-negative bacteria. The largest inhibition zones were obtained for the Gram-positive bacteria Staphylococcus aureus, ranging from 1.5 to 4.5 mm, depending on the concentration of CuMPs. The morphology of the fibres' surfaces was examined by means of scanning electron microscopy (SEM) and optical microscopy (OM). The changes in the polymer structure chemistry are studied by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray structure studies (WAXS and SAXS) and an energy-dispersive spectroscopy (EDS) analysis. The newly obtained bioactive polyamide fibres can be used in many areas, including medicine, clothing and environmental protection for the production of filters.

New Challenges and Prospective Applications of Three-Dimensional Bioactive Polymeric Hydrogels in Oral and Craniofacial Tissue Engineering: A Narrative Review

Regenerative medicine, and dentistry offers enormous potential for enhancing treatment results and has been fueled by bioengineering breakthroughs over the previous few decades. Bioengineered tissues and constructing functional structures capable of healing, maintaining, and regenerating damaged tissues and organs have had a broad influence on medicine and dentistry. Approaches for combining bioinspired materials, cells, and therapeutic chemicals are critical in stimulating tissue regeneration or as medicinal systems. Because of its capacity to maintain an unique 3D form, offer physical stability for the cells in produced tissues, and replicate the native tissues, hydrogels have been utilized as one of the most frequent tissue engineering scaffolds during the last twenty years. Hydrogels' high water content can provide an excellent conditions for cell viability as well as an architecture that mimics real tissues, bone, and cartilage. Hydrogels have been used to enable cell immobilization and growth factor application. This paper summarizes the features, structure, synthesis and production methods, uses, new challenges, and future prospects of bioactive polymeric hydrogels in dental and osseous tissue engineering of clinical, exploring, systematical and scientific applications.

3D porous bioceramic based boron-doped hydroxyapatite/baghdadite composite scaffolds for bone tissue engineering

Making composite scaffolds is one of the well-known methods to improve the properties of scaffolds used in bone tissue engineering. In this study, novel ceramic-based 3D porous composite scaffolds were successfully prepared using boron-doped hydroxyapatite, as the primary component, and baghdadite, as the secondary component. The effects of making composites on the properties of boron-doped hydroxyapatite-based scaffolds were investigated in terms of physicochemical, mechanical, and biological properties. The incorporation of baghdadite contributed to making more porous scaffolds (over 40%) with larger surface area and micropore volumes. The produced composite scaffolds almost solved the low degradation problem of boron-doped hydroxyapatite through the exhibition of higher biodegradation rates, which matched the degradation rate appropriate for the gradual transfer of loads from implants to newly formed bone tissues. Besides higher bioactivity, enhanced cell proliferation, as well as higher osteogenic differentiation (in scaffolds with baghdadite weight greater than 10%), were observed in composite scaffolds due to both physical and chemical modifications that occurred in composite scaffolds. Although our composite scaffolds were slightly weaker than boron-doped hydroxyapatite, their compressive strengths were higher than almost all composite scaffolds made by baghdadite incorporation in the literature. In fact, boron-doped hydroxyapatite provided a base for baghdadite to show mechanical strength suitable for cancellous bone defect treatments. Eventually, our novel composite scaffolds converged the advantages of both components to satisfy the various requirements needed for bone tissue engineering applications and take us one step forward on the road to fabricating an ideal scaffold.

Baghdadite: A Novel and Promising Calcium Silicate in Regenerative Dentistry and Medicine

For several years, ceramic biomaterials have been extensively utilized to rebuild and substitute for body tissues. Calcium silicates have been proven to exhibit excellent bioactivity due to apatite formation and cell proliferation stimulation, in addition to degradability at levels adequate for hard tissue formation. These ceramics' excellent biological characteristics have attracted researchers. Baghdadite is a calcium silicate incorporating zirconium ions that enhances human osteoblast multiplication and development, increasing mineralization, and ossification. It has currently received much interest in academic institutions and has been extensively explored in the form of permeable frameworks, varnishes, bone adhesive and gap fillings, microparticles, and nanospheres, particularly in a wide range of biomedical applications. This review article aims to summarize and analyze the most recent research on baghdadite's mechanical characteristics, apatite-forming capability, dissolution pattern, and physiochemical qualities as a scaffold for dentofacial tissuè regeneration purposes.

Recent advances on bioactive baghdadite ceramic for bone tissue engineering applications: 20 years of research and innovation (a review)

Various artificial bone graft substitutes based on ceramics have been developed over the last 20 years. Among them, calcium-silicate-based ceramics, which are osteoconductive and can attach directly to biological organs, have received great attention for bone tissue engineering applications. However, the degradation rate of calcium-silicate and bone formation is often out of balance, resulting in stress shielding (osteopenia). A new strategy to improve the drawbacks of these ceramics is incorporating trace elements such as Zn, Mg, and Zr into their lattice structures, enhancing their physical and biological properties. Recently, baghdadite (Ca₃ZrSi₂O₉) ceramic, one of the most appealing calcium-silicate-based ceramics, has demonstrated high bioactivity, biocompatibility, biodegradability, and cell interaction. Because of its physical, mechanical, and biological properties and ability to be shaped using various fabrication techniques, baghdadite has found high potential in various biomedical applications such as coatings, fillers, cement, scaffolds, and drug delivery systems. Undoubtedly, there is a high potential for this newly developed ceramic to contribute significantly to therapies to provide a tremendous clinical outcome. This review paper aims to summarize and discuss the most relevant studies performed on baghdadite-based ceramics and composites by focusing on their behavior in vivo and in vitro.

Preparation of gelatin-based hydrogels with tunable mechanical properties and modulation on cell-matrix interactions

Natural polymer material-based hydrogels normally show inferior mechanical stability and strength to bear large deformation and cyclic loading, therefore their applications in food, biomedical and tissue engineering fields are greatly limited. In this study, gelatin-based hydrogels with remarkable stability, as well as tunable mechanical properties, were prepared via a facile method known as the Hofmeister effect. The higher concentration of potassium sulfatesolution resulted in more dehydration and molecular chain folding, thus the treated hydrogels showed significantly improved tensile and compressive modulus, and decreased equilibrium swelling ratio, as revealed by scanning electron microscopy (SEM), Fourier transform infraredspectroscopy (FTIR), and mechanical tests, etc. Additionally, the reinforced hydrogels were recoverable and biocompatible to modulate the proliferation behavior of human umbilical vein endothelial cells. In conclusion, this paper provides a facile reference for tuning mechanical properties of gelatin-based hydrogels and cell-hydrogel interactions, which show potential capacity in tissue engineering and biomedical fields.