Objective To review recent advance in the research and appl ication of computer aided forming techniques for constructing bone tissue engineering scaffolds. Methods The l iterature concerning computer aided forming techniques for constructing bone tissue engineering scaffolds in recent years was reviewed extensively and summarized Results Several studies over last decade have focused on computer aided forming techniques for bone scaffold construction using various scaffold materials, which is based on computer aided design (CAD) and bone scaffold rapid prototyping (RP). CAD include medical CAD, STL, and reverse design. Reverse design can fully simulate normal bone tissue and could be very useful for the CAD. RP techniques include fused deposition model ing, three dimensional printing, selected laser sintering, three dimensional bioplotting, and low-temperature deposition manufacturing. These techniques provide a new way to construct bone tissue engineering scaffolds with complex internal structures. Conclusion With rapid development of molding and forming techniques, computer aided forming techniques are expected to provide ideal bone tissue engineering scaffolds.
Objective To fabricate a novel gelatinchondroitin sulfate-sodium hyaluronate tri-copolymer scaffold and to confirm the feasibility of serving as ascaffold for cartilage tissue engineering. Methods Different scaffolds was prepared with gelatin-chondroitin sulfatesodium hyaluronate tri-copolymer by varying the freezing temperatures (-20℃,-80℃ and liquid nitrogen). Pore size, porosity, inter pores and density were observed with light microscopy and scanning electron microscopy (SEM). The load-stiffness curves were compared between different scaffolds and normal cartilage. The number of MSCs attaching to different scaffolds and the function of cells were also detected with MTT colorimetric microassay. Results The pore size was 300±45, 230±30 and 45±10 μm; the porosity was 81%, 79% and 56%; the density was 9.41±0.25, 11.50±0.36 and 29.50±0.61 μg/mm3 respectively in different scaffolds fabricated at -20℃,-80℃ and liquid nitrogen; the latter two scaffolds had nearly the same mechanical property with normal cartilage; the cell adhesion rates were 85.0%, 87.5% and 56.3% respectively in different scaffolds and the scaffolds can mildly promote the proliferation of MSCs. Conclusion Gelatin-chondroitin sulfatesodium hyaluronate tricopolymer scaffold fabricated at -80℃ had proper pore size, porosity and mechanical property. It is a novel potential scaffold for cartilage tissue engineering.
Objective To study the feasibility of using mice marrow stromal stem cells(MSCs) as seed cells for tissue engineering cartilage to embed the seed cells in acellular cartilage matrix of human auricle. Methods Acellular cartilage matrix was made from human auricle cartilage. The MSCs were isolated from the nucleated cells fraction of mice marrow by centrifuge.The MSCs were embedded in acellular cartilage matrix. After 10 day’s combined culture, the specimens were observed with optical and electrical microscope.Results The MSCs could well proliferate in the acellular cartilage matrix. The cells were not well-distributed in acellular cartilage matrix. There were more cells in the peripheral part of the matrix than in the central part of the matrix. Most of the cells were in cartilaginous lacunae. There were 1 or 2 cells in every cartilaginous lacunae.Conclusion The MSCs can be used as seed cells of tissue engineering and can well proliferate in the acellular cartilage matrix and become tissue engineering cartilage.
To serve as carriers of cells and bioactive molecules, three-dimensional scaffolds play a key role in bone defect repair. The chemical component and microstructure of the scaffold can affect the mechanical properties and seed cells. A variety of fabrication techniques have been used in producing scaffolds, some made random porous structure, some created well-designed structure using rapid prototyping methods, and others prepared bio-derived materials as scaffolds. However, scaffolds may vary in their inner structure, mechanical properties and repairing efficiency as well because of different manufacturing methods. In this review, we overview the main achievements concerning the effects of material and microstructure on the mechanical performance, seed cells and defect repair of bone scaffolds.
ObjectiveTo summarize clinical experience and curative effect in applying three-dimensional mechanical equilibrium concept to cartilage scaffold construction in total auricular reconstruction.MethodsBetween June 2015 and June 2017, ninety-seven microtia patients (102 ears) were treated with total ear reconstruction by using tissue expanders. The patients included 43 males and 54 females and their age ranged from 7 to 45 years with an average of 14 years. There were 92 unilateral cases (45 in left side and 47 in right side) and 5 bilateral ones. There were 89 congenital cases and 8 secondary cases. According to microtia classification criteria, there were 21 cases of type Ⅱ, 67 cases of type Ⅲ, and 9 cases of type Ⅳ. Tissue expander was implanted in the first stage. In the second stage, autogenous cartilage was used to construct scaffolds which were covered by enlarged flap. According to the three-dimensional mechanical equilibrium concept, the stable ear scaffold was supported by the scaffolds base, the junction of helix and inferior crura of antihelix, and helix rim. The reconstructed ears were repaired in the third stage operation.ResultsAll patients had undergone ear reconstruction successfully and all incisions healed well. No infection, subcutaneous effusion, or hemorrhage occurred after operation. All skin flaps, grafts, and ear scaffolds survived completely. All patients received 5- to 17-month follow-up time (mean, 11.3 months) and follow-up time was more than 12 months in 61 cases (64 ears). All reconstructed ears stood upright, and subunits structure and sensory localization of reconstructed ears were clear, and the position, shape, size, and height of bilateral ears were basically symmetrical. Mastoid region scar hyperplasia occurred in 3 patients, which was relieved by anti-scar drugs injection. No scaffolds exposure, absorption, or structural deformation occurred during follow-up period.ConclusionApplication of three-dimensional mechanical equilibrium concept in cartilage scaffold construction can reduce the dosage of costal cartilage, obtain more stable scaffold, and acquire better aesthetic outcomes.
Objective To review the research progress of design of bone scaffolds with different single cell structures. Methods The related literature on the study of bone scaffolds with different single cell structures at home and abroad in recent years was extensively reviewed, and the research progress was summarized. ResultsThe single cell structure of bone scaffold can be divided into regular cell structure, irregular cell structure, cell structure designed based on topology optimization theory, and cell structure designed based on triply periodic minimal surface. Different single cell structures have different structural morphology and geometric characteristics, and the selection of single cell structure directly determines the mechanical properties and biological properties of bone scaffold. It is very important to choose a reasonable cell structure for bone scaffold to replace the original bone tissue. Conclusion Bone scaffolds have been widely studied, but there are many kinds of bone scaffolds at present, and the optimization of single cell structure should be considered comprehensively, which is helpful to develop bone scaffolds with excellent performance and provide effective support for bone tissue.
Objective To summarize the influence of microstructure on performance of triply-periodic minimal surface (TPMS) bone scaffolds. Methods The relevant literature on the microstructure of TPMS bone scaffolds both domestically and internationally in recent years was widely reviewed, and the research progress in the imfluence of microstructure on the performance of bone scaffolds was summarized. Results The microstructure characteristics of TPMS bone scaffolds, such as pore shape, porosity, pore size, curvature, specific surface area, and tortuosity, exert a profound influence on bone scaffold performance. By finely adjusting the above parameters, it becomes feasible to substantially optimize the structural mechanical characteristics of the scaffold, thereby effectively preempting the occurrence of stress shielding phenomena. Concurrently, the manipulation of these parameters can also optimize the scaffold’s biological performance, facilitating cell adhesion, proliferation, and growth, while facilitating the ingrowth and permeation of bone tissue. Ultimately, the ideal bone fusion results will obtain. Conclusion The microstructure significantly and substantially influences the performance of TPMS bone scaffolds. By deeply exploring the characteristics of these microstructure effects on the performance of bone scaffolds, the design of bone scaffolds can be further optimized to better match specific implantation regions.