Bone tissue regeneration and blood vessel formation are inseparable. How to realize the vascularization of bone repair scaffolds is an urgent problem in bone tissue engineering. The growth and development, mineralization maturity, reconstruction and remodeling, and tissue regeneration of bone are all based on forming an excellent vascularization network. In recent years, more and more researchers have used hydrogels to carry different cells, cytokines, metal ions and small molecules for in vitro vascularization and application in bone regeneration. Based on this background, this article reviews the hydrogel-based vascularization strategies in bone tissue engineering.
Objective To review the research and application progress of bioactive glass in bone repair. Methods The recently published literature concerning bioactive glass in bone repair was reviewed and summarized. Results Bioactive glass can classified different types, such as bioactive glass particulate, bioactive glass scaffold, bioactive glass coating, injectable bioactive glass cement, and bioactive glass delivery system. Bioactive glass has been well studied in the field of bone repair due to its excellent biological properties. Also, the remarkable progress has been made in various aspects. Conclusion Bioactive glass is a reliable material of bone repair and will play an even more important role in the future.
Objective To introduce the basic research and cl inical appl ication of the injectable bone repair biomaterials. Methods The recent original articles about the injectable bone repair biomaterials were extensively reviewed. Results The injectable bone repair biomaterials could fill irregularly shaped defects and might allow bone augmentation, both with minimal surgical intervention, and the injectable bone repair material had a good prospect by the medical profession and attach great importance to the academic material, but there were some deficiencies and shortcomings. Conclusion The injectable bone repair biomaterials may be a future approach to repair bone defect．
In recent years, 3D printing technology, as a new material processing technology, can precisely control the macroscopic and microstructure of biological scaffolds and has advantages that traditional manufacturing methods cannot match in the manufacture of complex bone repair scaffolds. Magnesium ion is one of the important trace elements of the human body. It participates in many physiological activities of the body and plays a very important role in maintaining the normal physiological function of the organism. In addition, magnesium ions also have the characteristics of promoting the secretion of osteogenic proteins by osteoblasts and osteogenic differentiation of mesenchymal stem cells. By combining with 3D printing technology, more and more personalized magnesium-based biological scaffolds have been produced and used in bone regeneration research in vivo and in vitro. Therefore, this article reviews the application and research progress of 3D printing magnesium-based biomaterials in the field of bone regeneration and repair.
ObjectiveTo observe and compare the effects of peptides on the repair of rabbit skull defects through two different binding modes of non-covalent and covalent, and the combination of carboxyl (-COOH) and amino (-NH2) groups with materials.MethodsTwenty-one 3-month-old male ordinary New Zealand white rabbits were numbered 1 to 42 on the left and right parietal bones. They were divided into 5 groups using a random number table, the control group (group A, 6 sides) and the material group 1, 2, 3, 4 (respectively group B, C, D, E, 9 sides in each group). All animals were prepared with 12-mm-diameter skull defect models, and bone morphogenetic protein 2 (BMP-2) non-covalently bound multiwalled carbon nanotubes (MWCNT)-COOH+poly (L-lactide) (PLLA), BMP-2 non-covalently bound MWCNT-NH2+PLLA, BMP-2 covalently bound MWCNT-COOH+PLLA, and BMP-2 covalently bound MWCNT-NH2+PLLA were implanted into the defects of groups B, C, D, and E, respectively. At 4, 8, and 12 weeks after operation, the samples were taken for CT scanning and three-dimensional reconstruction, the ratio of bone tissue regeneration volume to total volume and bone mineral density were measured, and the histological observation of HE staining and Masson trichrome staining were performed to quantitatively analyze the volume ratio of new bone tissue.ResultsCT scanning and three-dimensional reconstruction showed that with the extension of time, the defects in groups A-E were filled gradually, and the defect in group E was completely filled at 12 weeks after operation. HE staining and Masson trichrome staining showed that the volume of new bone tissue in each group gradually increased with time, and regenerated mature bone tissue appeared in groups D and E at 12 weeks after operation. Quantitative analysis showed that at 4, 8, and 12 weeks after operation, the ratio of bone tissue regeneration volume to total volume, bone mineral density, and the volume ratio of new bone tissue increased gradually over time; and at each time point, the above indexes increased gradually from group A to group E, and the differences between groups were significant (P<0.05).ConclusionThrough covalent binding and using -NH2 to bound peptides with materials, the best bone repair effect can be achieved.
Polyetheretherketone is one of the most commonly used materials for the production of orthopaedic implants, but the osseointegration capacity of polyetheretherketone is poor because of its bioinert surface, which greatly limits its clinical application. In recent years, scholars have carried out a lot of research on the modification of polyetheretherketone materials in order to improve its osseointegration capacity. At present, the modification of polyetheretherketone is mainly divided into surface modification and blend modification. Therefore, this paper summarizes the research progress of polyetheretherketone material modification technology and its influence on osseointegration from two aspects of surface modification and blend modification for polyetheretherketone materials used in the field of bone repair, so as to provide a reference for the improvement and transformation of polyetheretherketone materials for bone repair in the future.
ObjectiveTo evaluate the in vivo biological safety of porous zinc oxide (ZnO)/hydroxyapatite (HA) composite materials.MethodsThe porous ZnO/HA composite materials and porous HA materials were prepared by the spark plasma sintering technology. First, the materials were characterized, including scanning electron microscopy to observe the material structure, in vitro degradation experiments to detect the degradation rate of the materials, and inductively coupled plasma emission spectrometer to detect the concentration of Zn2+ dissolved out of the composite material degradation. Then the two kinds of material extracts were prepared for acute systemic toxicity test. Fifteen male Kunming mice were randomly divided into groups A, B, and C (n=5) and injected intraperitoneally with normal saline, HA extracts, and ZnO/HA extracts, respectively. The body mass of the mice was recorded before injection and at 24, 48, and 72 hours after injection. The liver and kidney tissues were taken at 72 hours for HE staining to evaluate the safety of the composite material. Finally, the biological safety of the material in vivo was evaluated by implantation experiment. The eighteen male New Zealand white rabbits were randomly divided into HA group and ZnO/HA group (n=9); a bilateral radius defect model (1 cm) was established, and the right forelimbs of the two groups were implanted with porous HA materials and porous ZnO/HA composite materials, respectively; the left untreated as a blank control. The general condition of the animals were observed after operation. The rabbit blood was collected at 1 day before operation and at 1 day, 1 week, 4 weeks, and 8 weeks after operation for routine blood test (inflammation-related indicators) and blood biochemistry (liver and kidney function-related indicators). X-ray films were taken at 4, 8, and 12 weeks after operation to observe the repair of bone defects.ResultsMaterial characterization showed that porous ZnO/HA composite materials had interconnected large and small pore structures with a pore size between 50 and 500 μm, which degraded faster than porous HA materials, and continuously and slowly dissolved Zn2+. The acute systemic toxicity test showed that the mice in each group had no abnormal performance after injection, and the body mass increased (P<0.05). HE staining showed that the cells shape and structure of liver and kidney tissue were normal. Animal implantation experiments showed that all rabbits survived until the experiment was completed; routine blood tests showed inflammation in each group (neutrophils, monocytes, and lymphocytes increased) at 1 day after operation, and all returned to normal at 8 weeks (P>0.05); compared with 1 day before operation, the content of inflammatory cells in the HA group increased at 1 day, 1 week, and 4 weeks after operation (P<0.05), and the ZnO/HA group increased at 1 day after operation (P<0.05); blood biochemistry showed that the liver and kidney function indexes were in the normal range; X-ray films showed that the ZnO/HA group had better osseointegration than the HA group at 4 weeks after operation.ConclusionThe porous ZnO/HA composite material has good in vivo biological safety and good bone repair ability, which is a potential bone repair material.
Objective To review the research progress on bone repair biomaterials with the function of recruiting endogenous mesenchymal stem cells (MSCs). Methods An extensive review of the relevant literature on bone repair biomaterials, particularly those designed to recruit endogenous MSCs, was conducted, encompassing both domestic and international studies from recent years. The construction methods and optimization strategies for these biomaterials were summarized. Additionally, future research directions and focal points concerning this material were proposed. Results With the advancement of tissue engineering technology, bone repair biomaterials have increasingly emerged as an ideal solution for addressing bone defects. MSCs serve as the most critical “seed cells” in bone tissue engineering. Historically, both MSCs and their derived exosomes have been utilized in bone repair biomaterials; however, challenges such as limited sources of MSCs and exosomes, low survival rates, and various other issues have persisted. To address these challenges, researchers are combining growth factors, bioactive peptides, specific aptamers, and other substances with biomaterials to develop constructs that facilitate stem cell recruitment. By optimizing mechanical properties, promoting vascular regeneration, and regulating the microenvironment, it is possible to create effective bone repair biomaterials that enhance stem cell recruitment. Conclusion In comparison to cytokines, phages, and metal ions, bioactive peptides and aptamers obtained through screening exhibit more specific and targeted recruitment functions. Future development directions for bone repair biomaterials will involve the modification of peptides and aptamers with targeted recruitment capabilities in biological materials, as well as the optimization of the mechanical properties of these materials to enhance vascular regeneration and adjust the microenvironment.
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.
Cell sheet technology refers to the preparation of cells into thin sheets, which retains a large amount of extracellular matrix, cell-cell junctions, and has a wide range of applications in the repair and regeneration of osteochondral tissues. This paper discusses the types, properties, and construction methods of stem cell sheets, and reviews the current research status of vascularization of stem cell sheets and their composite application with various cytokines and scaffolding materials for bone and cartilage repair, with the aim of exploring the direction of the further development of stem cell sheets in the field of bone and cartilage.