In search of a rapid method for vascular anastomosis with high quality,a compatative study was carried out to observe the results of laser welding of the saphenous artery of rabbit(0.45-0.85 indiameter)with the use of a degradable intraluninal bionterial support and the traditional method of suture anastomosis. The results showed that there was no significant difference observed between the two groups in the immediate and long patency rated and the occurrence of stenosis,However,the time ...
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.
Chitin was used as the stuffing material bonedefect in animal experiment. Radiological and his-tological examination showed that it had good bi-ologgical compatibility good strength, hemostaticeffect promoting tussue healing and no toxicity.Chitin could be degradated by enzyme and mightbe used as the bone supporting material for treament of bone defect.
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 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.
ObjectiveTo review the research progress of medicine biomaterials in prevention and treatment of adhesion after tendon injury, and to provide reference for clinical treatment.MethodsThe literature on the application of medical biomaterials in the prevention and treatment of tendon adhesions in recent years was reviewed, and the biological process, treatment methods, and current status of tendon adhesions were summarized.ResultsTendon adhesion as part of the healing process of the tendon is the biological response of the tendon to the injury and is also a common complication of joint dysfunction. Application of medical biomaterials can achieve better biological function of postoperative tendon by reducing the adhesion of peritendon tissues as far as possible without adversely affecting the tendon healing process.ConclusionThe use of medical biomaterials is conducive to reduce the adhesion of tendon after operation, and the appropriate anti-adhesion material should be selected according to the patients’ condition and surgical needs.
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 investigate cell cycle as a new tool to evaluate the biocompatibility of biomaterials.Methods The cell cycle and the expression of related genes were analyzed by the methods of immunocytochemistry, protein blotting, RT PCR and flow cytometry. Results The physical properteis, chemical properties and topological properities of biomaterials could not only influence cell cycle of the cells attached onto biomaterials but also affect the expression of related genes of target cells. Conclusion As an important extension of routine proliferation epxeriments, the study of cell cycle control will be great help for us to to study the cell group as an organic society. It revealed the balance between cell proliferation, cell differentiation and apotosis. It is suggested that the study of cell cycle control will play a key role in the research of tissue engineering.
ObjectiveTo investigate the mechanical properties of the novel compound calcium phosphate cement (CPC) biological material as well as the biological activity and osteogenesis effects of induced pluripotent stem cells (iPS) seeding on scaffold and compare their bone regeneration efficacy in cranial defects in rats.MethodsAc- cording to the different scaffold materials, the experiment was divided into 4 groups: pure CPC scaffold group (group A), CPC∶10%wt chitosan as 2∶1 ratio mixed scaffold group (group B), CPC∶10%wt chitosan∶whisker as 2∶1∶1 ratio mixed scaffold group (group C), and CPC∶10%wt chitosan∶whisker as 2∶1∶2 ratio mixed scaffold group (group D). Mechanical properties (bending strength, work-of-fracture, hardness, and modulus of elasticity) of each scaffold were detected. The scaffolds were cultured with fifth generation iPS-mesenchymal stem cells (MSCs), and the absorbance (A) values of each group were detected at 1, 3, 7, and 14 days by cell counting kit 8 (CCK-8) method; the alkaline phosphatase (ALP) activity, Live/Dead fluorescence staining and quantitative detection, ALP, Runx2, collagen typeⅠ, osteocalcin (OC), and bone morphogenetic protein 2 (BMP-2) gene expressions by RT-PCR were detected at 1, 7, and 14 days; and the alizarin red staining were detected at 1, 7, 14, and 21 days. Twenty-four 3-month-old male Sprague Dawley rats were used to establish the 8 mm-long skull bone defect model, and were randomly divided into 4 groups (n=6); 4 kinds of scaffold materials were implanted respectively. After 8 weeks, HE staining was used to observe the repair of bone defects and to detect the percentage of new bone volume and the density of neovascularization.ResultsThe bending strength, work-of-fracture, hardness, and modulus of elasticity in groups B, C, and D were significantly higher than those in group A, and in groups C, D than in group B, and in group D than in group C (P<0.05). CCK-8 assay showed that cell activity gradually increased with the increase of culture time, theA values in groups B, C, and D at 3, 7, 14 days were signifiantly higher than those in group A, and in groups C, D than in group B (P<0.05), but no significant difference was found between groups C and D (P>0.05). Live/Dead fluorescence staining showed that the proportion of living cells in groups B, C, and D at 7 and 14 days was significantly higher than that in group A (P<0.05), and in groups C, D at 7 days than in group B (P<0.05); but no significant difference was found between groups C and D (P>0.05). RT-PCR showed that the relative expressions of genes in groups B, C, and D at 7 and 14 days were significantly higher than those in group A, and in groups C, D than in group B (P<0.05); but no significant difference was found between groups C and D (P>0.05). Alizarin red staining showed that the red calcium deposition on the surface of scaffolds gradually deepened and thickened with the prolongation of culture time; theA values in groups B, C, and D at 14 and 21 days were significantly higher than those in group A (P<0.05), and in groups C and D than in group B (P<0.05), but no significant difference was found between groups C and D (P>0.05).In vivo repair experiments in animals showed that the new bone in each group was mainly filled with the space of scaffold material. Osteoblasts and neovascularization were surrounded by new bone tissue in the matrix, and osteoblasts were arranged on the new bone boundary. The new bone in groups B, C, and D increased significantly when compared with group A, and the new bone in groups C and D was significantly higher than that in group B. The percentage of new bone volume and the density of neovascularization in groups B, C, and D were significantly higher than those in group A, and in groups C and D than in group B (P<0.05); but no significant difference was found between groups C and D (P>0.05).ConclusionThe mechanical properties of the new reinforced composite scaffold made from composite chitosan, whisker, and CPC are obviously better than that of pure CPC scaffold material, which can meet the mechanical properties of cortical bone and cancellous bone. iPS-MSCs is attaching and proliferating on the new reinforced composite scaffold material, and the repair effect of bone tissue is good. It can meet the biological and osteogenic activity requirements of the implant materials in the bone defect repair.
The present study is aimed to investigate the early clinical effects of nano-hydroxyapatite/polyamide 66 intervertebral fusion cage (n-HA/PA66 cage) for the treatment of lumbar degenerative diseases. We selected 27 patients with lumbar degenerative diseases who were managed by posterior decompression or reset operation combined with n-HA/PA66 cage intervertebral fusion and internal fixation from August 2010 to January 2012. The oswestry disability index (ODI), low back and leg pain visual analogue score (VAS), and intervertebral height (IH) were evaluated at preoperation, 1 week postoperation and the last follow-up period, respectively. Intervertebral bony fusion was evaluated at the last follow-up time. The patients were followed up for 12-24 months (averaged 19 months). The ODI, VAS and IH were significantly improved at 1 week postoperation and the last follow-up time compared with those at preoperative period (P<0.05). But there was no significant difference between 1 week postoperative and the last follow-up time (P<0.05). Brantigan's standard was used to evaluate fusion at the last follow-up time. There were 19 patients with grade 5 fusion, 8 with grade 4 fusion, with a fusion rate of 100%, and none with grade 1-3 fusions. There was no cage translocation and internal fixation breakage. These results suggested that n-HA/PA66 cage was an ideal biological material in the posterior lumbar interbody fusion and internal fixation operation for treatment of lumbar degenerative diseases. It can effectively maintain the intervertebral height and keep a high rate of bony fusion. The early clinical effect has been satisfactory.