ObjectiveTo analyze the progress in biological tissue engineering scaffold materials and the clinical application, as well as product development status.
MethodsBased on extensive investigation in the status of research and application of biological tissue engineering scaffold materials, a comprehensive analysis was made. Meanwhile, a detailed analysis of research and product development was presented.
ResultsConsiderable progress has been achieved in research, products transformation, clinical application, and supervision of biological scaffold for tissue engineering. New directions, new technology, and new products are constantly emerging. With the continuous progress of science and technology and continuous improvement of life sciences theory, the new direction and new focus still need to be continuously adjusted in order to meet the clinical needs.
ConclusionFrom the aspect of industrial transformation feasibility, acellular scaffolds and extracellular matrix are the most promising new growth of both research and product development in this field.
ObjectiveTo summarize the research progress of tissue-engineered bile duct in recent years.
MethodsThe related literatures about the tissue-engineered bile duct were reviewed.
ResultsIn recent years, the research of tissue-engineered bile duct has made a breakthrough in scaffold materials, seed cells, growth factors etc. However, the tissue-engineered bile duct is still in the research stage of animal experiments, which can not be directly applied to clinical practice.
ConclusionsThe research of tissue-engineered bile duct becomes popular at present. With the rapid development of materials science and cell biology, the basic research and clinical application of tissue-engineered duct will be more in-depth research and extension, which might bring new ideas and therapeutic measures for patients with biliary defect or stenosis.
OBJECTIVE: To study the feasibility of calcium polyphosphate fiber (CPPF) as the scaffold material of tendon tissue engineering. METHODS: CPPF (15 microns in diameter) were woven to form pigtail of 3 mm x 2 mm transverse area; and the tensile strength, porous ratio and permeability ratio were evaluated in vitro. Tendon cells (5 x 10(4)/ml) derived from phalangeal flexor tendon of SD rats were co-culture with CPPF scaffold or CPPF scaffold resurfaced with collagen type-I within 1 week. The co-cultured specimens were examined under optical and electric scanning microscope. RESULTS: The tensile strength of CPPF scaffolds was (122.80 +/- 17.34) N; permeability ratio was 61.56% +/- 14.57%; and porous ratio was 50.29% +/- 8.16%. CPPF had no obvious adhesive interaction with tendon cells, while CPPF of surface modified with collagen type-I showed good adhesive interaction with tendon cells. CONCLUSION: The above results show that CPPF has some good physical characteristics as scaffold of tendon tissue engineering, but its surface should be modified with organic substance or even bioactive factors.
To summarize the medium-term cl inical result of bio-derived bone transplantation in orthopedics with tissue engineering technique. Methods From December 2000 to June 2001, 10 cases of various types of bone defect were treated with tissue engineered bone, which was constructed in vitro by allogenous osteoblasts from periosteum (1 × 106/ mL) with bio-derived bone scaffold following 3 to 7 days co-culture. Six men and 4 women were involved in this study, aged from 14 to 70 years with a median of 42 years. Among them, there were 2 cases of bone cyst, 1 case of non-union of old fracture, 6 cases of fresh comminuted fracture with bone defect, and 1 case of chronic suppurative ostemyel itis. The total weight of tissue engineered bone was 3-15 g in all the cases, averaged 7.3 g in each case. Results The wound in all the case healed by first intention. For 7 year follow up, bone union was completed within 3.0 to 4.5 months in 9 cases, but loosening occurred and the graft was taken out 1 year after operation in 1 case. The X-ray films showed that 9 cases achieved union except one who received resection of the head of humerus. No obvious abnormities were observed, and the function of affected l imbs met daily l ife and work. Conclusion Bio-derived tissue engineered bone has good osteogenesis. No obvious rejection and other compl ications are observed in the cl inical appl ication.
【Abstract】 Objective To compare the properties of collagen membranes before and after crossl inked and to establ ish the foundation of appl ication of collagen membranes. Methods Fresh bovine tendons were separated and collagen was extracted by washing, smashing and acetic acid dissolving. The collagen protein was determined by ultraviolet spectrophotometer and its characteristics were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), wavelength scanning and amino acids detecting. Collagen membranes were produced by lyophil ization. And then the biocharacteristics of the membranes before and after glutaraldehyde crossl inked were compared. BMSCs separated from volunteer’s bone marrow were seeded on collagen membranes before and after crossl inked by 2×103 in 100 μL medium, seven days after culture, the absorption spectrum of BMSCs was examined, and BMSCs were observed by scanning electron microscope (SEM). Results The contents of collagen protein were 2 mg/mL. The maximum absorption wave length appeared at about 230 nm. SDS-PAGE suggested that molecularweight of main bands was more than 66.2×103, the same as collagen marker from calf skin. There were 21.47% glycine, 12.04% pral ine and 10.18% hydroxyprol ine. No tryptophan was found. Before crossl inked, collagen membranes were in shape of white sponges and with big holes and the range of pH value was from 4.5 to 5.0. SEM showed reticular conformation and pore structure of collagen membranes, but the bore diameter was bigger. Their water-absorbing capacity was 61 times as much as their weight. The mechanical strength was 210 g/cm3. The dissolution time of collagenase was 90 minutes. After crossl inked, collagen membranes became thin, colorless, semi-transparent and compact with better tenacity. Under SEM, compact collagen fiber appeared reticular. There was lower water-absorbing capacity and pH value ranged from 6.5 to 7.0. The mechanical strength was 3 400 g/cm3 and the dissolution time of collagenase became longer. BMSCs could grow better either on before-crossl inked collagen membranes or on after-crossl inked ones. Conclusion As biomaterial scaffolds, after crossl inked collagen membranes were better than before-crossl inked ones.
ObjectiveTo review the properties of bio-derived hydrogels and their application and research progress in tissue engineering.
MethodsThe literature concerning the biol-derived hydrogels was extensively reviewed and analyzed.
ResultsBio-derived hydrogels can be divided into single-component hydrogels (collagen,hyaluronic acid,chitosan,alginate,silk fibroin,etc.) and multi-component hydrogels[Matrigel,the extract of extracellular matrix (ECM),and decellularized ECM].They have favorable biocompatibility and bioactivity because they are mostly extracted from the ECM of biological tissue.Among them,hydrogels derived from decellularized ECM,whose composition and structure are more in line with the requirements of bionics,have incomparable advantages and prospects.This kind of scaffold is the closest to the natural environment of the cell growth.
ConclusionBio-derived hydrogels have been widely used in tissue engineering research.Although there still exist many problems,such as the poor mechanical properties,rapid degradation,the immunogenicity or safety,vascularization,sterilization methods,and so on,with the deep-going study of optimization mechanism,desirable bio-derived hydrogels could be obtained,and thus be applied to clinical application.
Objective To investigate the possibility of repairing articular cartilage defects with the mesenchymal stem cells(MSCs) seeded type Ⅰ collagen-glycosaminoglycan(CG) matrices after being cultured with the chondrogenic differentiation medium. Methods The adherent population of MSCs from bone marrow of10 adult dogs were expanded in number to the 3rd passage. MSCs were seeded intothe dehydrothermal treatment (DHT) crosslinked CG matrices; 2×106 cells per 9mm diameter samples were taken. Chondrogenic differentiation was achieved by the induction media for 3 weeks. Cell contractility was evaluated by the measuement of the cell-mediated contraction of the CG matrices with time inculture.The in vitro formation of the cartilage was assessed by an assayemploying immunohistochemical identification of type Ⅱ collagen and by immunohistochemistry to demonstrate smooth muscle actin （SMA）. The cells seededingCGs wereimplanted into cartilage defectsof canine knee joints. Twelve weeks after surgery, the dogs were sacrificed and results were observed. Results There was significant contraction of the MSCsseeded DHT crosslinked CG scaffolds cultured in the cartilage induction medium. After 21 days, the MSCseeded DHT crosslinked matrices were contracted to 64.4%±0.3%; histologically, the pores were found to be compressedandthe contraction coupled with the newly synthesized matrix, transforming the MSCsseeded CG matrix into a solid tissue in most areas. The type Ⅱ collagen staining was positive. The SMA staining was positive when these MSCs were seeded and the contracted CGs were implanted into the cartilage defects of the canine knee joints to repair the cartilage defects. The function of the knee joints recovered and the solid cartilaginous tissue filled the cartilage defects. Conclusion The results demonstrates that MSCs grown in the CG matrices can produce a solid cartilaginous tissuecontaining type Ⅱ collagen after being cultured with the chondrogenic differentiation medium and implanted into cartilage defects. We hypothesize that the following steps can be performed in the chondrogenic process: ①MSCs express SMA, resulting in matrix contraction, thus achieving a required cell density (allowing the cells to operate in a necessary society)； ②Cells interact to form a type Ⅱ collagencontaining extracellular matrix (and cartilaginous tissue)； ③Other factors, suchas an applied mechanical stress, may be required to form a mature cartilage with the normal architecture.
Objective
To prepare the silk fibroin (SF)-chitosan (CS) scaffolds by adjusting the mass ratio between CS and SF, and test and compare the properties of the scaffolds at different mass ratios.
Methods
According to the mass ratios of 6
∶
4 (group A), 6
∶
8 (group B), and 6
∶
16 (group C) between SF and CS, CS-SF scaffolds were prepared by freeze-drying method, respectively. The material properties, porosity, the dissolubility in hot water, the modulus elasticity, and the water absorption expansion rate were measured; the aperture size and shape of scaffolds were observed by scanning electron microscope (SEM). Density gradient centrifugation method was used to isolate the bone marrow mesenchymal stell cells (BMSCs) of 4-week-old male Sprague Dawley rats. The BMSCs at passage 3 were seeded onto 3 scaffolds respectively, and then the proliferation of cells on the scaffolds was detected by MTS method.
Results
The results of fourier transform infrared spectroscopy proved that with the increased content of CS, the absorption peak of random coil/α helix structure (1 654 cm-1 and 1 540 cm-1) constantly decreased, but the absorption peak of corresponding to β-fold structure (1 628 cm-1 and 1 516 cm- 1) increased. The porosity was 87.36% ± 2.15% in group A, 77.82% ± 1.37% in group B, and 72.22% ± 1.37% in group C; the porosity of group A was significantly higher than that of groups B and C (P lt; 0.05), and the porosity of group B was significantly higher than that of group C (P lt; 0.05). The dissolubility in hot water was 0 in groups A and B, and was 3.12% ± 1.26% in group C. The scaffolds had good viscoelasticity in 3 groups; the modulus elasticity of 3 groups were consistent with the range of normal articular cartilage (4-15 kPa); no significant difference was found among 3 groups (F=5.523, P=0.054). The water absorption expansion rate was 1 528.52% ± 194.63% in group A, 1 078.22% ± 100.52% in group B, and 1 320.05% ± 179.97% in group C; the rate of group A was significantly higher than that of group B (P=0.05), but there was no significant difference between groups A and C and between groups B and C (P gt; 0.05). SEM results showed the aperture size of group A was between 50-250 μm, with good connectivity of pores; however, groups B and C had structure disturbance, with non-uniform aperture size and poor connectivity of pores. The growth curve results showed the number of living cells of group A was significantly higher than that of groups B and C at 1, 3, 5, and 7 days (P lt; 0.05); and there were significant differences between groups B and C at 3, 5, and 7 days (P lt; 0.05).
Conclusion
The CS-SF scaffold at a mass ratio of 6
∶
4 is applicable for cartilage tissue engineering.
ObjectiveTo observe the feasibility of acellular cartilage extracellular matrix (ACECM) oriented scaffold combined with chondrocytes to construct tissue engineered cartilage.MethodsChondrocytes from the healthy articular cartilage tissue of pig were isolated, cultured, and passaged. The 3rd passage chondrocytes were labeled by PKH26. After MTT demonstrated that PKH26 had no influence on the biological activity of chondrocytes, labeled and unlabeled chondrocytes were seeded on ACECM oriented scaffold and cultivated. The adhesion, growth, and distribution were evaluated by gross observation, inverted microscope, and fluorescence microscope. Scanning electron microscope was used to observe the cellular morphology after cultivation for 3 days. Type Ⅱ collagen immunofluorescent staining was used to check the secretion of extracellular matrix. In addition, the complex of labeled chondrocytes and ACECM oriented scaffold (cell-scaffold complex) was transplanted into the subcutaneous tissue of nude mouse. After transplantation, general physical conditions of nude mouse were observed, and the growth of cell-scaffold complex was observed by molecular fluorescent living imaging system. After 4 weeks, the neotissue was harvested to analyze the properties of articular cartilage tissue by gross morphology and histological staining (Safranin O staining, toluidine blue staining, and typeⅡcollagen immunohistochemical staining).ResultsAfter chondrocytes that were mainly polygon and cobblestone like shape were seeded and cultured on ACECM oriented scaffold for 7 days, the neotissue was translucency and tenacious and cells grew along the oriented scaffold well by inverted microscope and fluorescence microscope. In the subcutaneous microenvironment, the cell-scaffold complex was cartilage-like tissue and abundant cartilage extracellular matrix (typeⅡcollagen) was observed by histological staining and typeⅡcollagen immunohistochemical staining.ConclusionACECM oriented scaffold is benefit to the cell adhesion, proliferation, and oriented growth and successfully constructes the tissue engineered cartilage in nude mouse model, which demonstrates that the ACECM oriented scaffold is promise to be applied in cartilage tissue engineering.
