OBJECTIVE: To review the advance in materials of nerve conduit and Schwann cell transplantation for preparation of artificial nerve with tissue engineering technique. METHODS: Recent literatures about artificial nerve, nerve conduit and Schwann cell transplantation were extensively reviewed. RESULTS: Many biomaterials such as silicon, dacron, expanded polytetrafluoroethylene(ePTFE), polyester and chitin could be used as nerve conduits to repair nerve defect, the degradable biomaterials were better. The nerve conduit with intrinsic filaments could be used to bridge an extended gap in peripheral nerve. Purified and cultured Schwann cells were still bioactive. Axonal regeneration could be enhanced after implantation of Schwann cells into nerve conduit. CONCLUSION: The ideal artificial nerve is composed of three dimensional biodegradable nerve conduit and bioactive Schwann cells, Schwann cells can be distributed in nerve conduit just like Bünger’s band.
OBJECTIVE: To discuss the approaches of tissue engineered blood vessels (TEBV) reconstruction. METHODS: The recent literatures about TEBV were widely reviewed. We summarized various types of biomaterials served as scaffold for TEBV and evaluated the construction model of TEBV. And the biological properties of some TEBV were compared. RESULTS: Although the final model of construction of TEBV was not clear, reports in the last two years had shown several important advances in this exciting field. CONCLUSION: Mimicry of some or all of the properties of three layers of natural healthy blood vessels has been the strategy of all TEBV approaches.
Objective To investigate the influence of the exogenouscollagen on the function of cells in construction of artificial biotendon.Methods Three materials including human hair, carbon fiber(CF) and polyglycolic acid (PGA) were combined with exogenous collagen and co-cultured with standard transferred human embryonic tenocytes at a concentration of 3×106/mm3 in vitro. The cell number and morphology were observed under inverted microscope and scanning electron microscope after 2 hours, 3 days and 5 days.Results In the artificial biotendon combined with collagen, the cells concentrated around the materials and the cells adhering to the materials turned into round after 2 hours. After 3 days, the adhering cells increased. After 5 days, the shape of the cells changed from round to spindle.ConclusionExogenous collagen will facilitate the cells to adhere onto materials and proliferate.
Objective To summarize the latest developments in silk protein fiber as biomaterials and their applications in tissue engineering. Methods Recent original literature on silk protein fiber as biomaterials were reviewed, illustrating the properties of silk protein fiber biomaterials. Results The silk protein fiber has the same functions of supporting the cell adhesion, differentiation and growth as native collagen, and is renewed as novel biomaterials with good biocompatibility, unique mechanical properties and is degradable over a longer time. Conclusion Silk protein-fiber can be used as asuitable matrix for three dimensional cell culture in tissue engineering. It has a great potential applications in other fields.
OBJECTIVE To study the biocompatibility on bioactive glass ceramics (BGC) and polylactic acid (PLA) combined with cultured bone marrow stromal cells (BMSCs) in bone tissue engineering. METHODS BMSCs were cultured combined with BGC and PLA in vitro, and the morphological characters, cell proliferation, protein content, and alkaline phosphatase activity were detected. RESULTS: BMSCs could be attached to and extended on both BGC and PLA, and normally grown, proliferated, had active function. BGC could promote cell proliferation. CONCLUSION The results show that both BGC and PLA have good biocompatibility with BMSCs, they can be used as biomaterials for cell transplantation in tissue engineering.
Objective To investigate bone regeneration of the cell-biomaterial complex using strategies of tissue engineering based on cells.Methods Hydroxyapatite/collagen (HAC) sandwich composite was produced to mimic the natural extracellular matrix of bone, with type Ⅰ collagen servingas a template for apatite formation. A three-dimensional ploy-porous scaffoldwas developed by mixing HAC with poly(L-lactic acid) (PLA) using a thermally induced phase separation technique (TIPS). The rabbit periosteal cells were treated with 500 ng/ml of recombinant human bone morphogenetic protein 2(rhBMP-2), followed by seeded into pre-wet HAC-PLA scaffolds. Eighteen 3-month nude mice were implanted subcutaneously cell suspension (groupA, n=6), simple HAC-PLA scaffold (group B, n=6) and cell-biomaterial complex(group C, n=6) respectively.Results Using type Icollagen to template mineralization of calcium and phosphate in solution, we get HAC sandwich composite, mimicking the natural bone both in compositionand microstructure. The three dimensional HAC-PLA scaffold synthesized by TIPShad high porosity up to 90%, with pore size ranging from 50 μm to 300 μm. SEMexamination proved that the scaffold supported the adhesion and proliferation of the periosteal cells. Histology results showed new bone formation 8 weeks after implantation in group C. The surface of group A was smooth without neoplasma. Fibrous tissueinvasion occured in group B and no bone and cartilage formations were observed.Conclusion The constructed tissue engineering bone has emerged as another promising alternative for bone repair.
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.
OBJECTIVE: From the point of view of material science, the methods of tissue repair and defect reconstruct were discussed, including mesenchymal stem cells (MSCs), growth factors, gene therapy and tissue engineered tissue. METHODS: The advances in tissue engineering technologies were introduced based on the recent literature. RESULTS: Tissue engineering should solve the design and preparation of molecular scaffold, tissue vascularization and dynamic culture of cell on the scaffolds in vitro. CONCLUSION: Biomaterials play an important role in the tissue engineering. They can be used as the matrices of MSCs, the delivery carrier of growth factor, the culture scaffold of cell in bioreactors and delivery carrier of gene encoding growth factors.
The evaluation of blood compatibility of biomaterials is crucial for ensuring the clinical safety of implantable medical devices. To address the limitations of traditional testing methods in real-time monitoring and electrical property analysis, this study developed a portable electrical impedance tomography (EIT) system. The system uses a 16-electrode design, operates within a frequency range of 1 to 500 kHz, achieves a signal to noise ratio (SNR) of 69.54 dB at 50 kHz, and has a data collection speed of 20 frames per second. Experimental results show that the EIT system developed in this study is highly consistent with a microplate reader (R2=0.97) in detecting the hemolytic behavior of industrial-grade titanium (TA3) and titanium alloy—titanium 6 aluminum 4 vanadium (TC4) in anticoagulated bovine blood. Additionally, with the support of a multimodal image fusion Gauss-Newton one-step iterative algorithm, the system can accurately locate and monitor in real-time the dynamic changes in blood permeation and coagulation caused by TC4 in vivo. In conclusion, the EIT system developed in this study provides a new and effective method for evaluating the blood compatibility of biomaterials.
For the damage and loss of tissues and organs caused by urinary system diseases, the current clinical treatment methods have limitations. Tissue engineering provides a therapeutic method that can replace or regenerate damaged tissues and organs through the research of cells, biological scaffolds and biologically related molecules. As an emerging manufacturing technology, three-dimensional (3D) bioprinting technology can accurately control the biological materials carrying cells, which further promotes the development of tissue engineering. This article reviews the research progress and application of 3D bioprinting technology in tissue engineering of kidney, ureter, bladder, and urethra. Finally, the main current challenges and future prospects are discussed.