Scaffolds for bone tissue engineering (BTE) should accomplish appropriate mechanical, cell interaction, and new bone ingrowth properties. Among calcium phosphate (CaP) based bio-ceramics used for preparing scaffolds, biphasic calcium phosphate (BCP) is attracting great interest for fabricating BTE scaffolds owing to its excellent biocompatibility and osteoconductivity. Fused deposition modeling (FDM) is an additive manufacturing technology commonly used for modeling, prototyping, and production applications. It is one of techniques used for 3D printing. The main purpose of this study was to develop new fabrication process of BCP scaffolds based on extrusion moulding using a 3D printer. Through the 3D printer, we showed new fabrication process for making scaffold mould and extrusion device parts that could be combined with tension-compression test machine. Line width, pore size, and porosity of these fabricated BCP scaffolds were measured and calculated. Mechanical properties and cell proliferation results of these BCP scaffolds were then evaluated.

Recently, research on bone fracture and osteoplasty using ultrasonic bone surgery unit has been ongoing in the fields of dentistry, plastic surgery, and otorhinolaryngology. However, detailed data evaluation with ultrasonic bone surgery unit has not been conducted to date. In this study, we developed handpiece moving system (HMS) for cutting performance evaluation. In the experimental setup of HMS, a handpiece was immobilized, and bone samples from cortical bone of bovine leg were prepared. Also, the experimental process was described in detail, and a basic experiment was carried out to evaluate the cutting performance. Future study is required on all experimental process conditions by HMS.

Scaffold used as a carrier of the cell has been actively conducted using plenty of technology in tissue engineering. β-tricalcium phosphate (β-TCP) material has shown good biocompatibility and osteoconductive ability when it was implanted as a bone graft substitute in osseous defect in human and animal studies for bone regeneration. In this study, we fabricated the blended polycaprolactone (PCL) and β-TCP scaffold by the polymer deposition system (PDS). The PCL/β-TCP scaffold was fabricated at a temperature of 110℃, pressure of 650 kPa, and scan velocity of 100 mm/sec. The Overall geometry and size of the scaffold were fixed circle type with a diameter of 10 mm and a height of 4 mm. PCL/β-TCP scaffold was observed by scanning electron microscopy. Cell attachment and proliferation of the scaffold containing 30 wt% β-TCP was superior to those containing 10 wt% and 20 wt% β-TCP.

Solid free-form fabrication (SFF) technology was developed to fabricate three-dimensional (3D) scaffolds for tissue engineering (TE) applications. In this study, we developed a polymer deposition system (PDS) and created 3D microstructures using a bioresorbable polycaprolactone (PCL) polymer. Fabrication of 3D scaffolds by PDS requires a combination of several devices, including a heating system, dispenser, and motion controller. The system can process a polymer with extremely high precision by using a 200 μm nozzle. Based on scanning electron microscope (SEM) images, both the line width and the piled line height were fine and uniform. Several 3D micro-structures, including the ANU pattern (a pattern named after Andong National University), 45° pattern square, frame, cylindrical, triangular, cross-shaped, and hexagon, have been fabricated using the polymer deposition system.

This study presents the application of a polymer behavior model that considers fluid mechanics and heat transfer effects in a deposition system. The analysis of the polymer fluid properties is very important in the fabrication of precise microstructures. This fluid behavior model involves the calculation of velocity distribution and mass flow rates that include the effect of heat loss in the needle. The effectiveness of the proposed method was demonstrated by comparing estimated mass fluid rates with experimental values. The mass fluid rates under various process conditions, such as pressure, temperature, and needle size, reflected the actual deposition state relatively well, and the assumption that molten polycaprolactone(PCL) is a non-Newtonian fluid was reasonable. The successful fabrication of three-dimensional microstructures demonstrated that the model is valid for predicting the polymer behavior characteristics in the microstructure fabrication process. The results of this study can be used to investigate the effect of various parameters on fabricated structures before turning to experimental approaches.

In recent tissue engineering field, it is being reported that the fabrication of 3D scaffolds having high porous and controlled internal/external architectures can give potential contributions in cell adhesion, proliferation and differentiation. To fabricate these scaffolds, various solid free-form fabrication technologies are being applied. The solid free-form fabrication technology has made it possible to fabricate solid free-form 3D microstructures in layer-by-layer manner. In this research, we developed a multi-head deposition system (MHDS) and used design of experiment (DOE) to fabricate 3D scaffold having an optimized internal/external shape. Through the organization of experimental approach using DOE, the fabrication process of scaffold, which is composed of blended poly-caprolactone (PCL), poly-lactic-co-glycolic acid (PLGA) and tricalcium phosphate (TCP), is established to get uniform line width, line height and porosity efficiently. Moreover, the feasibility of application to the tissue engineering of MHDS is demonstrated by human bone marrow stromal cells (hBMSCs) proliferation test.