Objective To review new progress of related research of peri pheral nerve defect treatment with tissue engineering in recent years. Methods Domestic and internationl l iterature concerning peri pheral nerve defect treatment with tissue engineering was reviewed and analyzed. Results Releasing neurotrophic factors with sustained release technology included molecular biology techniques, poly (lactic-co-glycol ic acid) microspheres, and polyphosphate microspheres. The mixture of neurotrophic factors and ductus was implanted to the neural tube wall which could be degraded then releasing factors slowly. Seed cells which were the major source of active ingredients played an important role in the repair and reconstruction of tissue engineering products. The neural tube of Schwann cells made long nerve repair and the quality of nerve regeneration was improved. Nerve scaffold materials included natural and synthetic biodegradable materials. Tube structure usually was adopted for nerve scaffold, which performance would affect the nerve repair effects directly. Conclusion With the further research of tissue engineering, the treatment of peripheral nerve defects with tissue engineering has made significant progress.
OBJECTIVE: To prepare chitosan-gelatin/hydroxyapatite (CS-Gel/HA) composite scaffolds, and to investigate the influence of components and preparing conditions to their micromorphology. METHODS: The CS-Gel/HA composite scaffolds were prepared by phase-separation method. Micromorphology and porosity were detected by using scanning electron microscope and liquid displacement method respectively. RESULTS: Porous CS-Gel/HA composite scaffolds could be prepared by phase-separation method, and their density and porosity could be controlled by adjusting components and quenching temperature. CONCLUSION: The study suggests the feasibility of using CS-Gel/HA composite scaffolds for the transplantation of autogenous osteoblasts to regenerate bone tissue.
To serve as carriers of cells and bioactive molecules, three-dimensional scaffolds play a key role in bone defect repair. The chemical component and microstructure of the scaffold can affect the mechanical properties and seed cells. A variety of fabrication techniques have been used in producing scaffolds, some made random porous structure, some created well-designed structure using rapid prototyping methods, and others prepared bio-derived materials as scaffolds. However, scaffolds may vary in their inner structure, mechanical properties and repairing efficiency as well because of different manufacturing methods. In this review, we overview the main achievements concerning the effects of material and microstructure on the mechanical performance, seed cells and defect repair of bone scaffolds.
Objective To compare the difference of preparing the acellular larynx scaffold between perfusion method and immersion method, and find better way to make acellular larynx scaffold for tissue engineering. Methods Twenty 6-month-old male New Zealand rabbits, weighing 2.0-2.5 kg, were divided into perfusion group (n=10) and immersion group (n=10) at random. All the larynxes were excised in a sterile fashion. The acellular larynx scaffold was obtained by perfusionmethod and immersion method respectively, and then comparative examinations were performed by the macroscopicview, histological view, scanning electron microscope (SEM), cartilage vital ity assay and toluidine blue staining. ResultsMacroscopic view showed that the larynxes perfused by sodium dodecyl sulphate (SDS) became transparent after 2 hoursof perfusion, but the larynxes immersed by SDS over 16 hours still appeared pink-white. Histology and SEM indicated thatcompared with immersion group, perfusion group showed better acellular effect, more ventages and collagen fibers wereretained, no intact cell or nuclei remained in acellular matrix and chondrocytes were still survival. The porosity was 85.39% ± 3.16% in perfusion group and 34.72% ± 4.51% in immersion group, showing significant difference (P lt; 0.01). The chondrocyte vital ity rate of perfusion group (86.93% ± 1.52%) was higher than that of immersion group (77.73% ± 1.66%), showing significant difference (P lt; 0.01). Toluidine blue staining showed that the chondrocyte heterochromaty was ber in perfusion group than that in immersion group. Conclusion Compared with immersion method, perfusion method is a better way to construct acellular larynx scaffold because it can achieve better acellular effect and retain chondrocyte vital ity at the greatest extent in the acellular larynx scaffold.
ObjectiveTo summarize clinical experience and curative effect in applying three-dimensional mechanical equilibrium concept to cartilage scaffold construction in total auricular reconstruction.MethodsBetween June 2015 and June 2017, ninety-seven microtia patients (102 ears) were treated with total ear reconstruction by using tissue expanders. The patients included 43 males and 54 females and their age ranged from 7 to 45 years with an average of 14 years. There were 92 unilateral cases (45 in left side and 47 in right side) and 5 bilateral ones. There were 89 congenital cases and 8 secondary cases. According to microtia classification criteria, there were 21 cases of type Ⅱ, 67 cases of type Ⅲ, and 9 cases of type Ⅳ. Tissue expander was implanted in the first stage. In the second stage, autogenous cartilage was used to construct scaffolds which were covered by enlarged flap. According to the three-dimensional mechanical equilibrium concept, the stable ear scaffold was supported by the scaffolds base, the junction of helix and inferior crura of antihelix, and helix rim. The reconstructed ears were repaired in the third stage operation.ResultsAll patients had undergone ear reconstruction successfully and all incisions healed well. No infection, subcutaneous effusion, or hemorrhage occurred after operation. All skin flaps, grafts, and ear scaffolds survived completely. All patients received 5- to 17-month follow-up time (mean, 11.3 months) and follow-up time was more than 12 months in 61 cases (64 ears). All reconstructed ears stood upright, and subunits structure and sensory localization of reconstructed ears were clear, and the position, shape, size, and height of bilateral ears were basically symmetrical. Mastoid region scar hyperplasia occurred in 3 patients, which was relieved by anti-scar drugs injection. No scaffolds exposure, absorption, or structural deformation occurred during follow-up period.ConclusionApplication of three-dimensional mechanical equilibrium concept in cartilage scaffold construction can reduce the dosage of costal cartilage, obtain more stable scaffold, and acquire better aesthetic outcomes.
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.
Objective
To review the decellularized methods for obtaining extracellular matrix (ECM) and the applications of decellularized ECM scaffold in tissue engineering.
Methods
Recent and related literature was extensively and comprehensively reviewed. The decellularized methods were summarized and classified. The effects of different sterilization methods on decellularized scaffolds were analyzed; the evaluation criterion of extent of decellularization was put forward; and the application of decellularized ECM scaffold in different tissues and organs engineering field was summarized.
Results
The decellularized methods mainly include physical methods, chemical methods, and biological methods, and different decellularization methods have different effects on the extent of cell removal and ECM composition and structure. Therefore, the best decellularization method will be chosen according to the characteristics of the tissues and decellularization methods to achieve the ideal result.
Conclusion
It is very important to choose the appropriate decellularized method for preparing the biological materials desired by tissue engineering. The biological scaffolds prepared by decellularized methods will play an important role in tissue engineering and regenerative medicine.
Objective To comment on the recent advances of production and application of the bio-derived scaffold in the tissue engineered peripheral nerve. Methods The recent articles were systematically analyzed, and then the production methods of the bio-derived scaffold and its application to the tissue engineered peripheral nerve were evaluated and prospected. Results B iological tissues were processed by some methods to produce the bio-derived materials. These mat erials could maintain the structure and components of the tissues. Moreover, the immunogenicity of these materials was reduced. Conclusion Application of the bio-derived materials is a trend in the fabricating scaffold of the tissue en gineered peripheral nerve.
Replacement of diseased retinal pigment epithelium (RPE) cells with healthy RPE cells by transplantation is one option to treat several retinal degenerative diseases including age-related macular degeneration, which are caused by RPE loss and dysfunction. A cellular scaffold as a carrier for transplanted cells, may hold immense promise for facilitating cell migration and promoting the integration of RPE cells into the host environment. Scaffolds can be prepared from a variety of natural and synthetic materials. Strategies, such as surface modification and structure adjustment, can improve the biomimetic properties of the scaffolds, optimize cell attachment and cellular function following transplantation and lay a foundation of clinical application in the future.
Objective
To investigate the feasibility of fabricating an oriented scaffold combined with chondrogenic-induced bone marrow mesenchymal stem cells (BMSCs) for enhancement of the biomechanical property of tissue engineered cartilage in vivo.
Methods
Temperature gradient-guided thermal-induced phase separation was used to fabricate an oriented cartilage extracellular matrix-derived scaffold composed of microtubules arranged in parallel in vertical section. No-oriented scaffold was fabricated by simple freeze-drying. Mechanical property of oriented and non-oriented scaffold was determined by measurement of compressive modulus. Oriented and non-oriented scaffolds were seeded with chondrogenic-induced BMSCs, which were obtained from the New Zealand white rabbits. Proliferation, morphological characteristics, and the distribution of the cells on the scaffolds were analyzed by MTT assay and scanning electron microscope. Then cell-scaffold composites were implanted subcutaneously in the dorsa of nude mice. At 2 and 4 weeks after implantation, the samples were harvested for evaluating biochemical, histological, and biomechanical properties.
Results
The compressive modulus of oriented scaffold was significantly higher than that of non-oriented scaffold (t=201.099, P=0.000). The cell proliferation on the oriented scaffold was significantly higher than that on the non-oriented scaffold from 3 to 9 days (P lt; 0.05). At 4 weeks, collagen type II immunohistochemical staining, safranin O staining, and toluidine blue staining showed positive results in all samples, but negative for collagen type I. There were numerous parallel giant bundles of densely packed collagen fibers with chondrocyte-like cells on the oriented-structure constructs. Total DNA, glycosaminoglycan (GAG), and collagen contents increased with time, and no significant difference was found between 2 groups (P gt; 0.05). The compressive modulus of the oriented tissue engineered cartilage was significantly higher than that of the non-oriented tissue engineered cartilage at 2 and 4 weeks after implantation (P lt; 0.05). Total DNA, GAG, collagen contents, and compressive modulus in the 2 tissue engineered cartilages were significantly lower than those in normal cartilage (P lt; 0.05).
Conclusion
Oriented extracellular matrix-derived scaffold can enhance the biomechanical property of tissue engineered cartilage and thus it represents a promising approach to cartilage tissue engineering.
