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In this study, we investigated the effect of heat treatment (HT) and hot isostatic press (HIP) on the corrosion behavior of Ti6Al4 V, manufactured by electron beam melting (EBM) additive manufacturing. The preliminary results showed that the thermal process makes the columnar structure more pronounced and the α-lathe coarser compared to EBM. The ß phase disappeared with the aging treatment and when increasing the HIP temperature treatment. According the open circuit potential (E ocp) behavior of samples, the HIP3 sample had performed more positive corrosion potential than rivals after 2 h of immersion probably due to equiaxed grain with coarser α-late and the absence of the ß phase. In adverse, inferior corrosion behavior was observed for HIP1 because of a higher quantity of the ß phase causing probably galvanic corrosion. The HIP process leads to a lower corrosion potential than EBM. At least one protective oxide layer formation was observed for all samples at the anodic branch, and the current density was lower for the HT3 sample. The microstructure analysis revealed the presence of the ß-phase in the form of needle-like for the HT1 sample and HIP1 in the corroded area. Furthermore, the EDS line analysis showed the presence of aluminum with oxygen at the edge of the corrosion area for HIP1 suggesting aluminum plays a barrier against degradation. On the other hand, the HT1 showed higher impedance resistance due to the coarser α-lathe microstructure and well-defined ß phase.

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Additive manufacturing is growing in the area of dentistry and orthopedics due to the potential for the fabrication of individual implants. In this study, fused deposition modeling which is the most popular method was used to produce 3D scaffolds having a grid pattern from the polyurethane (PU) filament. Then, this scaffold was coated with boric acid (BA) with the thermionic vacuum arc technique. The microstructure analysis showed the macro-pores having a dimension of ~ 0.16 mm2. The BA coating increased the roughness in adverse decreased the wettability. The presence of BA on the scaffold before and after cell culture was confirmed by FESEM-EDS and ATR-FTIR. The Cell proliferation and osteogenic differentiation capacity of dental pulp stem cells (DPSCs) on uncoated and coated printed 3D PU scaffolds were also investigated. On the third day, cell viability was found to be higher (1.3-fold) in the groups containing BA. However, on the seventh day, the increase in cell proliferation in the PU+BA group was found to be less than in the other groups. According to Ca deposition analysis and Alizarin Red staining, PU+BA increased the calcium accumulation in the cells in both osteogenic induced and non-induced conditions at day 14. According to gene expression analysis, the Runx2 expression was not detected in PU+BA groups with and without differentiation medium (p ≤0.05). The expression of OCN was persistently increased up to 21-fold and 48-fold in cells on PU and PU+BA in osteogenic differentiation medium group after 14 days compared to control group (p ≤0.05). DSPP expression was observed only in PU+BA in osteogenic differentiation medium group. In line with the results that we have obtained, our 3D printed scaffolds have properties to trigger the differentiation of DPSCs cells in terms of osteogenicity.

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Bone tissue is composed of organic minerals and cells. It has the capacity to heal for certain minor damages, but when the bone defects surpass the critical threshold, they need fixing. Bone regeneration through natural and synthetic biodegradable materials requires various steps, such as manufacturing methods and materials selection. A successful biodegradable bone graft should have a high surface area/volume ratio, strength, and a biocompatible, porous structure capable of promoting cell adhesion, proliferation, and differentiation. Considering these requirements, the electrospinning technique is promising for creating functional nano-sized scaffolds. The multi-axial methods, such as coaxial and triaxial electrospinning, are the most popular techniques to produce double or tri-layered scaffolds, respectively. Recently, stem cell culture on scaffolds and the application of osteogenic differentiation protocols on these scaffolds have opened new possibilities in the field of biomaterials research. This review discusses an overview of the progress in coaxial and triaxial technology through biodegradable composite bone materials. The review also carefully elaborates the osteogenic differentiation using stem cells and their performance with nano-sized scaffolds.

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Purpose: Transplantation of autologous and/or allogeneic blood vessels is the most convenient treatment for vascular diseases. With regard to extensive need for blood vessels, developments in vascular tissue engineering are contributing greatly. In this study, our aim is to create intact small-diameter tubular vascular grafts cultivated in pulsatile flow bioreactor. Materials and Methods: CD146+ cell-based small-diameter vascular grafts were fabricated with ECM/glycosaminoglycans and polyurethane nanofibers. Characterization of the vascular graft was performed by SEM and WST-1. To mimic blood circulation in the bioreactor, human CD34+ cells cultured in megakaryocytes/platelets medium; then these cells were transferred inside of the vascular graft to mimic blood circulation. Cell differentiation was evaluated by flow cytometry and colony assay. Wright-Giemsa staining and polyploidy analysis were performed to show the differentiated cell population inside of the vascular graft. Anti-thrombogenic properties of the blood vessel were demonstrated by IF. Results: Polyurethane nanofibers provided a suitable environment for Human umbilical cord vein endothelial cells (HUVECs), and no significant cytotoxic effect was observed. Scanning electron microscopy (SEM) analysis of the tubular graft showed that under perfusion HUVECs, smooth muscle cells (SMCs) and fibroblasts formed layers that aligned on each other, respectively. The vascular graft was strong with a tensile strength of 0.70 MPa and elastic modulus of 0.007 GPa. When cultured in a bioreactor system, platelet adhesion to the vascular graft was remarkably low. Conclusion: In conclusion, this vascular graft may hold the potential to regenerate functional small-diameter vessels for cardiovascular tissue repair.

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OBJECTIVE: The aim of this study was to define the chemical composition, morphology and crystallography of powdered fish heads of the species Argyrosomus regius for bone graft biomaterial applications. METHODS: Two sizes of powder were prepared by different grinding methods; Powder A (coarse, d50=68.5 µm) and Powder B (fine, d50=19.1 µm). Samples were analyzed using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), thermogravimetry (TG), and energy dispersive X-ray spectroscopy (EDS). RESULTS: The powder was mainly composed of aragonite (CaCO3) and calcite (CaCO3). The XRD pattern of Powder A and B matched standard aragonite and calcite patterns. In addition, the calcium oxide (CaO) phase was found after the calcination of Powder A. Thermogravimetry analysis confirmed total mass losses of 43.6% and 47.3% in Powders A and B, respectively. CONCLUSION: The microstructure of Powder A was mainly composed of different sizes and tubular shape, whereas Powder B showed agglomerated particles. The high quantity of CaO and other oxides resemble the chemical composition of bone. In general, the powder can be considered as bone graft after transformation to hydroxyapatite phase.

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