Objective To evaluate the biocompatibility of a new bone matrix material (NBM) composed of both organic and inorganic materials for bone tissue engineering. Methods Osteoblasts combined with NBM in vitro were cultured. The morphological characteristics was observed; cell proliferation, protein content and basic alkaline phosphatase(ALP) activity were measured. NBM combined with osteoblasts were implanted into the skeletal muscles of rabbits and the osteogenic potential of NBM was evaluated through contraat microscope, scanning electromicroscope and histological examination. In vitro osteoblasts could attach and proliferate well in the NBM, secreting lots of extracellular matrix; NBM did not cause the inhibition of proliferation and ALP activity of osteoblasts. While in vivo experiment of the NBM with osteoblasts showed that a large number of lymphacytes and phagocytes invading into the inner of the material in the rabbit skeletalmuscle were seen after 4 weeks of implantation and that no new bone formation was observed after 8 weeks. Conclusion This biocompat ibility difference between in vitro and in vivo may be due to the immunogenity of NBM which causes cellular immuno reaction so as to destroy the osteogenic environment. The immunoreaction between the host and the organic-inorganic composite materials in tissue engineering should be paid more attention to.
Objective To investigate the latest development of tissue engineeredregenerative medicine in industrialization, with the intention to direct work in practical area. Methods A complete insight of regenerative medicine in industrialization was obtained through referring to update publications, visiting related websites, as well as learning from practical experience. Results The aerial view of the future of regenerative medicine was got based on knowledge of four different tissue engineering projects. Conclusion All present efforts should be devoted to regenerative medicine area meeting the industrialized trends.
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.
OBJECTIVE: To study the feasibility of the formation of allogeneic tissue-engineered cartilage of certain shape in immunocompetent animal using the injectable biomaterial. METHODS: Fresh newborn rabbits’ articular cartilages were obtained under sterile condition (lt; 6 hours after death) and incubated in the sterile 0.3% type II collagenase solution. After digestion of 8 to 12 hours, the solution was filtered through a 150 micron nylon mesh and centrifuged, then the chondrocytes were washed twice with phosphate buffered saline (PBS) and mixed with the biomaterial to create a final cell density of 5 x 107/ml. The cell-biomaterial admixture was injected into rabbits subcutaneously 0.3 ml each point while we drew the needle back in order to form the neocartilage in the shape of cudgel, and the control groups were injected with only the biomaterial or the suspension of chondrocytes with the density of 5 x 10(7)/ml. After 4, 6, 8 and 12 weeks, the neocartilages were harvested to analyze. RESULTS: The new nodes could be touched subcutaneously after 2 weeks. In the sections of the samples harvested after 4 weeks, it was found that the matrix secreted and the collagen formed. After 6 weeks and later than that, the neocartilages were mature and the biomaterial was almost completely degraded. The cudgel-shaped samples of neocartilage could be formed by injection. In the experiment group, there was no obvious immune rejection response. On the contrary, there were no neocartilage formed in the control group. CONCLUSION: The injectable biomaterial is a relatively ideal biomaterial for tissue engineering, and it is feasible to form allogeneic tissue engineered cartilage of certain shape by injection in an immunocompetent animal.
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.
Objective To review the osteoimmunomodulatory effects and related mechanisms of inorganic biomaterials in the process of bone repair. Methods A wide range of relevant domestic and foreign literature was reviewed, the characteristics of various inorganic biomaterials in the process of bone repair were summarized, and the osteoimmunomodulatory mechanism in the process of bone repair was discussed. Results Immune cells play a very important role in the dynamic balance of bone tissue. Inorganic biomaterials can directly regulate the immune cells in the body by changing their surface roughness, surface wettability, and other physical and chemical properties, constructing a suitable immune microenvironment, and then realizing dynamic regulation of bone repair. Conclusion Inorganic biomaterials are a class of biomaterials that are widely used in bone repair. Fully understanding the role of inorganic biomaterials in immunomodulation during bone repair will help to design novel bone immunomodulatory scaffolds for bone repair.
Objective To illustrate the effect and complication of orthopedic applications for biodegradable and absorbable internal fixation of fractures, and to indicate the existent problem and research aspect currently. Methods The recent literatures on orthopedic applications and study of biodegradable and absorbable internal fixation for fractures were reviewed. The effect of biodegradable materials on bone healing was summarized. Results It is good for the stability of fracture fixation and result of treeatment. The biodegradable and absorbable internal fixation fractures had no adverse effect on bone healing. Conclusion There will be more widespread application for biodegradable and absorbable materials in orthopedics, but the intensive research should be carried out to prevent its complication.
Objective To investigate the currently-used biomaterials in reparative and reconstructive surgery and to clarify the relationship between the development of biomaterials and the progress of reparative and reconstructive surgery. Methods Based on the author’s many years’ scientific researches and combined with the literature available at home and abroad, the biomaterials used in the clinical practice, and their kinds and application fields were summarized. Results Based on the sufficient knowledge of the component structure of biomaterials and the patient’s pathological status, the matching biomaterials could be designed and developed. According to the analysis on some common defects occurring in the skin, bone, cartilage, vocalcord, nerve, and drum membrane, the methods of repairing the defects with biomaterials that we had developed, such as collagen, chitosan, and hyaluronate, achieved good results. Conclusion The rapid development of biomaterials can greatly promote progress of reparative and reconstructive surgery andthere exists a dependence relationship between the two. The related histological responses and the importance of biological estimation after implantation of biomaterials should be emphasized.
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.
ObjectiveTo summarize the research progress of interfacial tissue engineering in rotator cuff repair.MethodsThe recent literature at home and abroad concerning interfacial tissue engineering in rotator cuff repair was analysed and summarized.ResultsInterfacial tissue engineering is to reconstruct complex and hierarchical interfacial tissues through a variety of methods to repair or regenerate damaged joints of different tissues. Interfacial tissue engineering in rotator cuff repair mainly includes seed cells, growth factors, biomaterials, oxygen concentration, and mechanical stimulation.ConclusionThe best strategy for rotator cuff healing and regeneration requires not only the use of biomaterials with gradient changes, but also the combination of seed cells, growth factors, and specific culture conditions (such as oxygen concentration and mechanical stimulation). However, the clinical transformation of the relevant treatment is still a very slow process.