Qingxi Hu

The mechanical properties of bone tissue engineering scaffold fabricating via selective laser sintering

Performance of bone tissue depends on porous scaffold microstructures with specific porosity characteristics that influence the behavior of the ingrown cells. The mechanical properties of porous tissue scaffolds are important for their biomechanical tissue engineering application. In this study, the composite materials powder was developed for the selective laser sintering process, and the parameters of selective laser sintering were optimized. With the aim of evaluating the influence of porosity on mechanical properties, we have studied the load limits for three specimens of scaffolds which have different porosity. Youngs modulus was computed by determining the slope of the stress - strain curve along the elastic portion of the deformation. In addition, the final element analysis (FEA) module of UG NX4 was used to analyze these scaffolds. The results showed that the bone tissue engineering scaffolds were fabricated by SLS technology have good mechanical properties, which have good potential for tissue engineering applications.

The influence of prefreezing temperature on pore structure in freeze-dried β-TCP scaffolds

A combined method of tricalcium phosphate (TCP) scaffold production, which comprised negative mold and scaffold fabrication, was reported in this study. The negative mold structure was designed by computer and fabricated by fused deposition modeling (FDM) technology, while the TCP scaffold was produced by freeze-drying technology under different prefreezing temperatures of −10°C, −30°C, and −86°C and thermal treatment to get β-TCP. The scaffold structure was evaluated with X-ray, scanning electron microscopy (SEM), compressive mechanical testing, and microcomputerized tomography (micro-CT). The cell–scaffold interaction was studied by culturing dog bone marrow stromal cells (BMSCs) on the scaffolds and assessing differentiated BMSC function by measuring cellular alkaline phosphatase (ALP) activity. The results showed good interconnectivity and good pore distribution with the pore size ranging from 50 to 250 µm and compressive modulus of 1.18 MPa at a prefreezing temperatures of −10°C. In vitro cell culture results indicated that the porous scaffolds were not toxic to bone cells. These results demonstrate that rapid prototyping and freeze-drying technologies for creating β-TCP scaffolds are promising for bone tissue engineering.

Fabrication of porous β-TCP scaffolds by combination of rapid prototyping and freeze drying technology

The scaffold with exact shape and polygradient inner structure was necessary for bone tissue engineering scaffolds to facilitate cells infiltration and proliferation. A novel method of designing and preparing bone tissue engineering scaffolds with polygradient controllable structure of both macro and micro pores was proposed in this paper. By integrating rapid prototyping and freeze drying technology, the macro and micro pores were formed respectively. The size, shape and quantity of micropores were controlled by slurry concentration. The sintered β-TCP porous scaffolds were with connective macropores of approximately 400µm and micropores of 50∼300µm. The chemical composition, porosity and mechanical properties of scaffolds were measured and analyzed. The detected results indicated that the β-TCP scaffolds could fulfill the requirements of tissue engineering.

Effect of microstructure on the mechanical properties and biology performance of bone tissue scaffolds using selective laser sintering

Porous β-tricalcium phosphate (β-TCP) ceramic scaffolds with axially oriented macropore and random micropore were produced by selective laser sintering (SLS) process. Microstructure parameters including pore size, pore size distribution and interconnectivity were quantified by microcomputed tomography. Compressive mechanical properties were tested. The porosity of sintered scaffolds was over 60%. The range of average compressive modulus and ultimate strength was 24.38∼30.64MPa and 1.64∼2.35MPa, respectively. Dog bone marrow stromal cells (BMSCs) were seeded in the prepared scaffolds. Cell proliferation and osteogenic differentiation on the scaffolds were evaluated with the alkaline phosphatase (ALP) activity and osteocalcin (OCN) content.

Bone Tissue Engineering Using B-Tricalcium Phosphate Scaffolds Fabricated Via Selective Laser Sintering

β - tricalcium phosphate (β-TCP) is a biodegradable ceramic with potential application for bone replacement. In this work, porous β-TCP scaffolds were fabricated via selective laser sintering, which is a rapid prototyping technique. β-TCP and glue composite was developed as a powder material to product porous scaffolds, using this computer-controlled sintering and deposition process. The β-TCP scaffolds were produced with the strut size 800 µm and max porosity 55.4%. Compressive modulus ranged from 13MPa to 18Mpa, and shrinkage was about 26%. Analysis of the measured data shows a high correlation between the scaffold porosity and the compressive properties based on SLS process relationship.

Influence of Microstructure on the Binder Ratio of B-TCP Tissue Scaffolds Using Selective Laser Sintering

The growing interest in scaffold-guided tissue engineering (TE) to guide and support cell proliferation in the repair and replacement of bone defects gave rise to the quest for a precise. Rapid prototyping (RP) has been identified as a promising technique capable of building complex objects with pre-designed macro- and microstructures. Calcium phosphate ceramics are biocompatible and may develop interactions with human living bone tissues. They are used clinically on the surface of orthopedic implants to improve primary fixation or in the form of porous blocks. The research focused on the macro and micro-structure of using the selective laser sintering (SLS) technique for creating porous tissue engineering scaffolds. The composite blends obtained by physical blending nano TCP and micro polymer powder binders. The SLS-fabricated test specimens were characterized using XRD and scanning electron microscopy. The total porous volume of the ceramics was over 70% and the pore size from several μm to 600μm. The results obtained ascertained that SLS-fabricated scaffolds have good potential for TE applications.Copyright