Tissue engineering scaffolds with oxygen generating elements have shown to be able to increase the level of oxygen and cell survivability in specific conditions. In this study, biphasic calcium phosphate (BCP) scaffolds with the composition of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (β-TCP), which have shown a great potential for bone tissue engineering applications, were fabricated by a direct-write assembly (robocasting) technique. Then, the three-dimensional (3D)-printed scaffolds were coated with different ratios of an oxygen releasing agent, calcium peroxide (CPO), which encapsulated within a polycaprolactone (PCL) matrix through dip-coating, and used for in situ production of oxygen in the implanted sites. The structure, composition and morphology of the prepared scaffolds were characterized by different techniques. The oxygen release kinetics and biological investigations of the scaffolds were also studied in vitro. The results showed that oxygen release behaviour was sustained and dependant on the concentration of CPO encapsulated in the PCL coating matrix. It was also demonstrated that the coated scaffolds, having 3% CPO in the coating system, could provide a great potential for promoting bone ingrowth with improving osteoblast cells viability and proliferation under hypoxic conditions. The findings indicated that the prepared scaffolds could play a significant role in engineering of large bone tissue implants with limitations in oxygen diffusion.
Scaffold design from xenogeneic bone has the potential for tissue engineering (TE). However, major difficulties impede this potential, such as the wide range of properties in natural bone. In this study, sintered cortical bones from different parts of a bovine-femur impregnated with biodegradable poly(ethylene glycol) (PEG) binder by liquid phase adsorption were investigated. Flexural mechanical properties of the PEG-treated scaffolds showed that the scaffold is stiffer and stronger at a sintering condition of 1000°C compared with 900°C. In vitro cytotoxicity of the scaffolds evaluated by Alamar Blue assay and microscopic tests on human fibroblast cells is better at 1000°C compared with that at 900°C. Furthermore, in vitro biocompatibility and flexural property of scaffolds derived from different parts of a femur depend on morphology and heat-treatment condition. Therefore, the fabricated scaffolds from the distal and proximal parts at 1000°C are potential candidates for hard and soft TE applications, respectively.
Wear debris, of deferent sizes, shapes and quantities, generated in artificial hip and knees is largely confined to the bone and joint interface. This debris interacts with periprosthetic tissue and may cause aseptic loosening. The purpose of this review is to summarize and collate findings of the recent demonstrations on debris characterization and their biological response that influences the occurrence in implant migration. A systematic review of peer-reviewed literature is performed, based on inclusion and exclusion criteria addressing mainly debris isolation, characterization, and biologic responses. Results show that debris characterization largely depends on their appropriate and accurate isolation protocol. The particles are found to be non-uniform in size and non-homogeneously distributed into the periprosthetic tissues. In addition, the sizes, shapes, and volumes of the particles are influenced by the types of joints, bearing geometry, material combination, and lubricant. Phagocytosis of wear debris is size dependent; high doses of submicron-sized particles induce significant level of secretion of bone resorbing factors. However, articles on wear debris from engineered surfaces (patterned and coated) are lacking. The findings suggest considering debris morphology as an important parameter to evaluate joint simulator and newly developed implant materials.
Acrylic and epoxy are common types of resin used in fabricating sockets. Different types of resin will affect the internal surface of a laminated socket. This paper is to determine the best combination of ratio for epoxy and acrylic resin for a laminated prosthesis socket and to evaluate the surface profile analysis of different combinations of laminated prosthetic sockets for surface roughness. Transfemoral sockets were created using various resin-to-hardener ratios of 2:1, 3:1, 3:2, 2:3, and 1:3 for epoxy resin and 100:1, 100:2, 100:3, 100:4, and 100:5 for acrylic resin. Eight layers of stockinette consisting of four elastic stockinette and four Perlon stockinette were used. A sample with a size of 4 cm × 6 cm was cut out from the socket on the lateral side below the Greater Trochanter area. The Mitutoyo Sj-210 Surface Tester stylus was run through the sample and gave the Average Surface Roughness value (Ra), Root Mean Square Roughness value (Rq), and Ten-Point Mean Roughness value (Rz). Epoxy resin shows a smoother surface compared to acrylic resin with Ra values of is 0.766 µm, 0.9716 µm, 0.9847 µm and 1.5461 µm with 3:2, 3:1, 2:1 and 2:3 ratio respectively. However, for epoxy resin with ratio 1:3, the resin does not cure with the hardener. As for acrylic resin the Ra values are 1.0086 µm, 2.362 µm, 3.372 µm, 4.762 µm and 6.074 µm with 100: 1, 100:2, 100:5, 100:4 and 100:3 ratios, respectively. Epoxy resin is a better choice in fabricating a laminated socket considering the surface produced is smoother.