Papers by Keyword: Artificial Bone

Abstract: The design of engineered bone substitutes takes biocompatibility and mechanical compatibility into account as prerequisite requirements. Titanium (Ti) and hydroxyapatite (HA) with chemical formula of Ca₁₀(PO₄)₆(OH)₂, show good biocompatibility and are known as biomaterials. To combine metal powder (Ti) and ceramic powder (HA) as a composite material with mechanical properties comparable to those of natural bones needs strategy. In this work, powder metallurgy process was employed to produce Ti-HA composites, with nominal HA powder contents in the range of 0-100 vol.%. Mixtures of Ti and HA powders were pressed in a rigid die. Sintering was performed in vacuum atmosphere. The as-sintered specimens were tested on biocompatibility in a human-osteoblast cells. It was found that processing and materials parameters, including compaction pressure, control the composite microstructures and mechanical properties. Laboratory bone tissue culturing showed that a bone tissue could grow on the artificial bones (sintered Ti-HA composites).

Abstract: Scaffolds material is the key factor for bone tissue engineering, and construction of the scaffolds is also an important part. Adopting the biocompatible, biodegradable, hydroxyapatite (HAP) and sodium alginate (SA) as the molding material, using three-dimensional printing technology, choosing cross grid filling paths, we manufactured the artificial bones through self-developed 3D printing equipment. Then we measured and analyzed important parameters of the work, and did composite culture experiment. It can be seen that the prepared artificial bone scaffold has good biocompatibility. The paper provides a reference for the study of bone tissue engineering materials.

Abstract: A novel fabrication of degradable scaffold is presented by using several biomaterials and growth factor (GF). Chitosan fibers can be braided into the internal fiber microstructure of the scaffold by a three-dimensional braiding (3DB) method, and rapid prototype & rapid tools techniques can be used to rapidly fabricate the outer shape mold of the scaffold. The scaffolds with 3D fiber architecture had obviously accelerated bone regeneration in comparison with the control. In detail, the materials biodegraded inside and outside and the bone ingrowth first occurred along the chitosan fibers in the scaffold. In summary, the method in this paper not only can be easily shaped but also cannot change the bio-properties of materials and GF since it does not need high temperature sintering and not produce heat, so the actions of the several biomaterials for bone regeneration interacted simultaneously through the interconnectivity macrochannels in the in-vivo scaffolds, which left by the biodegradation of the internal fiber.

Abstract: The loading force of the artificial bone implanted into the human body and the flowing, growth and deposition of cells were influenced by the gradient porous structure. The software of ANSYS Workbench was used in the paper for the stress and strain analysis of the gradient porous structure of the established 3D artificial bone. The variation of the maximum equivalent stress and maximum equivalent strain and elastic modulus changed through the changing of the loading force and porosity. Basis on meeting the mechanical properties, the porosity was used as the index for the optimization of the porous structure of the artificial bone. And it also laid the foundation for the subsequent laser sintering.

Abstract: Artificial bone implant is concerned to improve their substantial features such as biocompatibility and mechanical properties. Ti-Nb alloys were considered to be one of the competitive materials because of their good biocompatibility and pseudoelasticity. In a present work, the effect of Zr addition as a third element on mechanical properties and pseudoelasticity of Ti-Nb alloys with Nb-content of 22-23at% were investigated by using cycling tests. The alloy ingots were fabricated by an arc melting method. The ingots were homogenization treated at 1273 K for 3.6ks followed by cold-rolled to a reduction ratio of 90% in thickness. All specimens were heat-treated at 873 K and some of them were aging treated at temperature ranging from 573 to 673 K after heat-treatment. Pseudoelasticity and mechanical behavior were evaluated by cycling test at room temperature. The results suggested that psuedoelasticity was confirmed in specimens without aging treatment irrespective of alloy compositions. Maximum recovery strain recovery increases with increasing Zr content. From all information acquired, it can be concluded that Ti-22Nb-(3-4)Zr(at.%) and Ti-23Nb-(2-3)Zr(at.%) alloys are the most optimum for artificial bone.

Abstract: Bone matrix consists of organic and inorganic components. Organic phase mainly contributes to flexibility of bone while inorganic phase being responsible for the rigidity and hardness of the bone. Due to the biocompatibility of ceramics many forms of them have been used as the bone replacement and as the repair material. Hydroxyapatite which also exists in the natural structure of bone is one of those ceramics used as a component of bone cement. In order to modify the physical properties of prepared bone composite structures, some additives are included within the structure. In this study, a silicate material is included as an inorganic filler together with hydroxyapatite. Bis-GMA and HEMA were used as organic matrix. The prepared composites were than immersed in SBF and FTIR, SEM, hardness analyses were performed on the samples before and after the immersion. The results were reported in later part. It was observed that the precipitation of hydroxyapatite occurred after the immersion of samples in SBF and the hardness values were increased for each sample.

Abstract: Biodegradable polymer has been widely used in surgical suture, dressing, artificial bone and other bone-related applications. However, when compared with the human cortical bone, the pure polymer obviously did not have enough strength. The present study aimed to give preliminary insights from a pilot study of designing a scaffold of polylactic acid ply yarns composited with stainless steel (SS) braids. To evaluate the fabrication processes and alkali effects on the individual materials, the different heating temperature and alkali treating time and alkali concentration were applied to clarify the changes in mechanical strength. The experimental results showed that the strength was not significant declined with alkali and heating treatments. The retained mechanical strength was kept at 100-120 MPa and ultimately led to bone-like mechanical properties.

Abstract: In this work, we focused on the manufacture of artificial bone for medical replacement based on the combination of individual properties of ceramic and polymer. Here, periosteum was fabricated with a HAp (Hydroxylapatite) frame, while compact bone was fabricated from multi-layer electro-spun PS (polystyrene)/PCL (polycaprolactone) using biocompatible collagen glue. Spongy bone is formed from PCL/PLGA spongy loading BCP (Biphasic Calcium Phosphate) powder coated collagen. SEM images showed successful fabrication of the artificial bone scaffold through a combination of electro-spinning, extrusion, and use of the slurry method.

Abstract: To fabricate an artificial bone, the degradation rate of which is adjustable, porosity and pore size is controllable, and internal continuity is good, a device is developed with nano-sized hydroxyapatite as raw material, micron-sized spot of high-power laser as energy, and selective sintering as technology to fabricate three-dimensional porous. Its basic composition, design ideas, features and working principle are introduced. The feeding mechanical system, sintering system, and laser focusing system are described in detail. The motion precision and laser-spot control precision meet with the requirements with testing.

Abstract: Large osseous defects are difficult to treat because of deficient blood supply on the defected area. To get sufficient blood supply, we designed to establish the adenovirus simultaneously encoding both VEGF and Ang-1 (pAd-VIA) to accelerate the formation of new vessels in the process of bone defect repair. The construction of the adenovirus was performed according to the method reported by Tong-Chuan HE with a tiny modification. Three kinds of adenoviruses were acquired. They are adenovirus pAd-VIA simultaneously encoding VEGF and Ang-1, adenovirus pAd-VEGF encoding VEGF, and adenovirus pAd-Ang-1 encoding Ang-1. The adenovirus prepared in this study could successfully transfer VEGF and Ang-1 into mesenchymal stem cells(MSCs) with high efficiency. Two-gene modified artificial bone was established by use of these adenovirus. In the end, the two-gene modified artificial bone was proved to have good biocompatibility and biological function. Study reports presented here will pave the way for further exploration of vascularization in the process of large osseous defects repair.