Membrane guided tissue regeneration is new biological concept. The basic theory of this concept includes the belief that during the healing process of wound, the different cells will show different speed of cell migration and regeneration in the wound. If an appropriate membrane being placed to form a mechanical barrier, so that only the needed cells can grow into that area and prevent others from going in, thus resulting in the creation of a guided area where the needed cells can undergo proliferation and differentiation under protection in completing an ideal tissue regeneration and repair. In this article, the experimental researches on the application of membrane guided tissue regeneration in the repair of tubular bone defects, skull defects and faciomaxillary defects were reviewed from literatures, and the degradable and non-degradable materials were introduced, particularly. The pros and cons of this method and the materials were evaluated. It is believed that this technique will push forward the progress in bone biology and reconstructive surgery.
ObjectiveTo summarize the developments of oxygen-generating materials as biomaterials and its applications in tissue engineering. MethodsThe recent literature on oxygen-generating materials as biomaterials was extensively reviewed, illustrating the properties and applications of oxygen-generating materials in tissue engineering. ResultsOxygen-generating materials as biomaterials have good biocompatibility and degradability. It supports the cell adhesion differentiation and growth. It is used for repairing liver, pancreas, myocardium, and so on. After modification, oxygen-generating materials can be extensively used in tissue engineering. ConclusionOxygen-generating materials is a good biomaterial, which has a great potential applications in tissue engineering.
ObjectiveTo explore the feasibility of three-dimensional (3D) bioprinted adipose-derived stem cells (ADSCs) combined with gelatin methacryloyl (GelMA) to construct tissue engineered cartilage.MethodsAdipose tissue voluntarily donated by liposuction patients was collected to isolate and culture human ADSCs (hADSCs). The third generation cells were mixed with GelMA hydrogel and photoinitiator to make biological ink. The hADSCs-GelMA composite scaffold was prepared by 3D bioprinting technology, and it was observed in general, and observed by scanning electron microscope after cultured for 1 day and chondrogenic induction culture for 14 days. After cultured for 1, 4, and 7 days, the composite scaffolds were taken for live/dead cell staining to observe cell survival rate; and cell counting kit 8 (CCK-8) method was used to detect cell proliferation. The composite scaffold samples cultured in cartilage induction for 14 days were taken as the experimental group, and the composite scaffolds cultured in complete medium for 14 days were used as the control group. Real-time fluorescent quantitative PCR (qRT-PCR) was performed to detect cartilage formation. The relative expression levels of the mRNA of cartilage matrix gene [(aggrecan, ACAN)], chondrogenic regulatory factor (SOX9), cartilage-specific gene [collagen type Ⅱ A1 (COLⅡA1)], and cartilage hypertrophy marker gene [collagen type ⅩA1 (COLⅩA1)] were detected. The 3D bioprinted hADSCs-GelMA composite scaffold (experimental group) and the blank GelMA hydrogel scaffold without cells (control group) cultured for 14 days of chondrogenesis were implanted into the subcutaneous pockets of the back of nude mice respectively, and the materials were taken after 4 weeks, and gross observation, Safranin O staining, Alcian blue staining, and collagen type Ⅱ immunohistochemical staining were performed to observe the cartilage formation in the composite scaffold.ResultsMacroscope and scanning electron microscope observations showed that the hADSCs-GelMA composite scaffolds had a stable and regular structure. The cell viability could be maintained at 80%-90% at 1, 4, and 7 days after printing, and the differences between different time points were significant (P<0.05). The results of CCK-8 experiment showed that the cells in the scaffold showed continuous proliferation after printing. After 14 days of chondrogenic induction and culture on the composite scaffold, the expressions of ACAN, SOX9, and COLⅡA1 were significantly up-regulated (P<0.05), the expression of COLⅩA1 was significantly down-regulated (P<0.05). The scaffold was taken out at 4 weeks after implantation. The structure of the scaffold was complete and clear. Histological and immunohistochemical results showed that cartilage matrix and collagen type Ⅱ were deposited, and there was cartilage lacuna formation, which confirmed the formation of cartilage tissue.ConclusionThe 3D bioprinted hADSCs-GelMA composite scaffold has a stable 3D structure and high cell viability, and can be induced differentiation into cartilage tissue, which can be used to construct tissue engineered cartilage in vivo and in vitro.
OBJECTIVE: To review the advance in materials of nerve conduit and Schwann cell transplantation for preparation of artificial nerve with tissue engineering technique. METHODS: Recent literatures about artificial nerve, nerve conduit and Schwann cell transplantation were extensively reviewed. RESULTS: Many biomaterials such as silicon, dacron, expanded polytetrafluoroethylene(ePTFE), polyester and chitin could be used as nerve conduits to repair nerve defect, the degradable biomaterials were better. The nerve conduit with intrinsic filaments could be used to bridge an extended gap in peripheral nerve. Purified and cultured Schwann cells were still bioactive. Axonal regeneration could be enhanced after implantation of Schwann cells into nerve conduit. CONCLUSION: The ideal artificial nerve is composed of three dimensional biodegradable nerve conduit and bioactive Schwann cells, Schwann cells can be distributed in nerve conduit just like Bünger’s band.
Thiry wistar rats were used and divided in 2 groups. A segment of 6mm was excised in the sciatic nerve which were then bridged with chitin and skelal muscle. at 4,8,12 weeks after operation, In the chitin group a satisfactory regeneration of nerve fibers was evident with electrophysiologic and histologic examinations, and HRP retrogade labelling evaluation. The possible mechanism of enhancing nerve regeneration of chitin was also discussed.
Objective To summarize the developmental process of biomedical materials and regenerative medicine. Methods After reviewing and analyzing the literature concerned, we put forward the developmental direction of biomedical materials and regenerative medicine in the future. Results Biomedical materials developed from the first and second-generations to the third-generation in the 1990s. Regenerative medicine was able to help the injured tissues and organs to be regenerated by the use of the capability of healing themselves. This kind of medicine included the technologies of the stem cells and the cloning, the tissue engineering, the substitute tissues and organs, xenotransplantation and soon. Conclusion The third-generation biomaterials possess the following two properties: degradation and bioactivity; and they can help the body heal itself once implanted. Regenerative medicine is a rapidly advancing field that opens a new and exciting opportunity for completely revolutionary therapeutic modalities and technologies.
Objective To summarize the latest developments in silk protein fiber as biomaterials and their applications in tissue engineering. Methods Recent original literature on silk protein fiber as biomaterials were reviewed, illustrating the properties of silk protein fiber biomaterials. Results The silk protein fiber has the same functions of supporting the cell adhesion, differentiation and growth as native collagen, and is renewed as novel biomaterials with good biocompatibility, unique mechanical properties and is degradable over a longer time. Conclusion Silk protein-fiber can be used as asuitable matrix for three dimensional cell culture in tissue engineering. It has a great potential applications in other fields.
Objective To sum up the recent progress of common bone graft substitute and to forecast the possible directions for further research. Methods Recent original articles about investigation and appl ication for bone graft substitute were extensively reviewed. Several common bone graft substitutes were selected and expounded in different categories. Results Bone graft was an essential treatment in order to provide structural support, fill bone cavity and promote bone defect heal ing. The gold standard for bone graft was autograft which is subject to many restrictions. In recent years, theresearch and development of bone graft substitute have received publ ic attention. A very great progress has been made in the research and appl ication of allograft bones, synthetic bones and engineered bones, and some research results have been put into use for real products. Conclusion There still exist many problems in present bone graft substitutes. Combining various biomaterials and using the specific processing technology to develop a biomaterial which has the similar mechanical and chemical properties and physical structures to autograft so as to promote bone defect heal ing is the direction for future research.
Objective To investigate bone regeneration of the cell-biomaterial complex using strategies of tissue engineering based on cells.Methods Hydroxyapatite/collagen (HAC) sandwich composite was produced to mimic the natural extracellular matrix of bone, with type Ⅰ collagen servingas a template for apatite formation. A three-dimensional ploy-porous scaffoldwas developed by mixing HAC with poly(L-lactic acid) (PLA) using a thermally induced phase separation technique (TIPS). The rabbit periosteal cells were treated with 500 ng/ml of recombinant human bone morphogenetic protein 2(rhBMP-2), followed by seeded into pre-wet HAC-PLA scaffolds. Eighteen 3-month nude mice were implanted subcutaneously cell suspension (groupA, n=6), simple HAC-PLA scaffold (group B, n=6) and cell-biomaterial complex(group C, n=6) respectively.Results Using type Icollagen to template mineralization of calcium and phosphate in solution, we get HAC sandwich composite, mimicking the natural bone both in compositionand microstructure. The three dimensional HAC-PLA scaffold synthesized by TIPShad high porosity up to 90%, with pore size ranging from 50 μm to 300 μm. SEMexamination proved that the scaffold supported the adhesion and proliferation of the periosteal cells. Histology results showed new bone formation 8 weeks after implantation in group C. The surface of group A was smooth without neoplasma. Fibrous tissueinvasion occured in group B and no bone and cartilage formations were observed.Conclusion The constructed tissue engineering bone has emerged as another promising alternative for bone repair.