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BACKGROUND:Three-dimensional self-assembling peptide nanofiber hydrogel scaffold can simulate the in vivo microenvironment and provide a structural model for cells, which promotes the right composition of extracel ular matrix and cel growth, as wel as improves the cel functions. OBJECTIVE:To review the fundamental research and the experimental study of the self-assembling peptide nanofiber scaffold in the nerve tissue engineering. METHODS:Literatures concerning basic and experimental studies on the self-assembling peptide nanofiber scaffold in the nerve tissue engineering were reviewed via searching PubMed and VIP databases (2000/2013) using the key words of“self-assembling peptide, nanofiber scaffold, RADA16, nerve tissue engineering, neural stem cel . RESULTS AND CONCLUSION:Self-assembling peptide nanofiber scaffold is a novel and ideal tissue engineering material which provides new method for nerve injury repairing, for it not only solves the problem of poor compatibility between the material and cells, but also plays a much more pivotal role in maintaining three-dimensional properties, promoting cel activities and mimicking the extracel ular matrix, which is superior to other materials. However, there stil exist some chal enges in the area of self-assembling peptides, including short-term issues such as integrating of self-assembling peptide with bio-macromolecular material or relatively developed traditional transplant;and long-term issues such as adapting immune system in vivo, treating targets within cells and anticipating the future fate of highly integrated scaffolds.
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BACKGROUND:Due to the much higher requirement of biocompatibility and anticoagulant of smal-diameter vascular grafts than those of large-diameter ones, in situ blood vessel regeneration occurs as a new research direction. OBJECTIVE:To summarize the recent research development of electrospun smal-diameter scaffolds and to explore the application of in situ blood vessel regeneration and the development tendency. METHODS:The first author retrieved China National Knowledge Infrastructure database, Wanfang data and ISI Web of Knowledge foreign database to retrieve literatures addressing the fabrication of electrospun smal-diameter nanofibrous vascular grafts, surface modification and mimicking extracel ular matrix, as wel as the evaluation of biocompatibility and security after grafting. RESULTS AND CONCLUSION:Electrospun smal-diameter nanofibrous vascular grafts have emerged as promising candidates in vascular tissue engineering. By using both natural and synthetic polymers, the scaffolds can achieve a good balance between mechanical property and biocompatibility. Meanwhile, the fabrication of multi-layered vascular scaffolds, functional surface modification and mimicking extracel ular matrix structural y and functional y are now becoming attractive research directions. However, at current stage, electrospun vascular scaffolds used clinical y are basical y formed by synthetic materials, which have limited biocompatibility and anticoagulant activity. In this case, more efforts should be paid to find an optimal ratio between natural and synthetic materials for the improvement of biocompatibility and anticoagulant ability of smal-diameter vascular grafts.
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BACKGROUND:Titanium has been widely used in dental implantation because of its good biocompatibility, mechanical properties and its similar elastic modulus to the bone. OBJECTIVE:To summarize three strategies for surface modification of titanium implants:physical modification, chemical modification and biochemical modification. METHODS:PubMed and CNKI databases were searched for articles published from January 2007 to February 2013, and the key words were“titanium, implant, surface modification, osseointegration”in English and Chinese, respectively. Articles which are closely related to titanium implant surface modification and osseointegration were included, and repetitive articles were removed. RESULTS AND CONCLUSION:After preliminary search, 199 articles were found. According to the inclusion criteria and exclusion criteria, 76 articles were further analyzed. Titanium implant is a bioinert material, and thus the researchers focus on surface modification to activate the titanium implant so as to possess biological function and achieve early osseointegration. Implant surface modification strategies include three perspectives:physical modification, chemical modification and biochemical modification which can shorten the period of implant therapy and achieve early osseointegration and higher binding strength. The future research trend is to combine three strategies and to further explore the molecular basis of mechanism at the interface between implant and organism cel and the tissue in order to use better surface modification technology to fulfil the early and more stable osseointegration between the implant and bone tissue.
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BACKGROUND:Based on variational principle and weighting technology of three-dimensional finite element method, human teeth with a complex morphology can be modeled, which helps to understand the stress distribution of dental hard tissue and prosthesis during the dynamic repair process. OBJECTIVE:To comprehensively analyze the three-dimensional finite element studies concerning biomechanics of dental prostheses, focusing on the effects of metal crown, porcelain thickness, root canal preparation and fil ing on the tooth stress. METHODS:A computer-based search of PubMed (1993-04/2012-09), China Academic Journal Network Publishing Database (2001-2008), and VIP (2001-2008) was performed by the first author to retrieve articles concerning the effects of metal crown, porcelain thickness, root canal preparation and fil ing on the tooth stress. The keywords were“porcelain-fused-to-metal, finite element method, stress analysis, root canal”in English and Chinese. Articles with repetitive contents or meta-analysis were ruled out. Then 40 articles were suitable for further analysis.RESULTS AND CONCLUSION:Finite element method has important significance to establish high-fidelity and high-accuracy models in oral medicine, thereby providing effective biomechanical information for the root canal treatment and post-treatment repair. Scholars continue to explore the stress distribution of dental prostheses during chewing. This review summarizes the stress changes of post and core crowns, supporting reference for further research. Three-dimensional finite element method can be used to build nonlinear three-dimensional finite element models with anisotropic biomechanical characteristics, and can gradual yimprove the transition from static analysis to a dynamic analysis, truly achieving accurate simulation of oral biology and dental morphology as wel as chewing function of the teeth.
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BACKGROUND:Antibiotic bone cement is the important method for the prevention and treatment of infection after artificial hip replacement and renovation. OBJECTIVE:To review the research progress of antibiotic bone cement. METHODS:A computer-based online search was performed in PubMed database, CNKI database, Chinese Biomedical Literature database, VIP database and Wanfang database for the literatures from 1978 to 2012. The key words were“bone cement, antibiotic bone cement, infection, joint replacement”in English and Chinese. RESUTLS AND CONCLUSION:A total of 335 literatures were screened out. Final y, 29 literatures were included for in-depth analysis after the primary screen through reading the title, abstract and ful-text. Antibiotic bone cement has been widely used in the treatment of infection after artificial joint replacement and renovation as it can reduce the risk of infection after initial joint replacement and renovation. The material properties and mechanical properties wil not change after bone cement mixed with appropriate amount of antibiotic. Different antibiotics in the bone cement have different release rates, which were closely related with the porosity of bone cement. Adding the additive that used for increasing the porosity of bone cement can increase the antibiotic release.
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10.3969/j.issn.2095-4344.2013.25.018
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10.3969/j.issn.2095-4344.2013.25.019
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10.3969/j.issn.2095-4344.2013.25.020
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BACKGROUND:Polyvinyl alcohol is a biocompatible and biodegradable polymer. It is widely used in clinical areas because of its water-soluble, film forming, emulsification, adhesiveness, tasteless, and nontoxic. OBJECTIVE:To review the applications of polyvinyl alcohol and its composite materials in bone, cartilage, skin, vessels and other tissue engineering scaffolds. METHODS:A computer-based online search of CNKI database from January 2000 to December 2011, PubMed database and Elsevier (ScienceDirect) database from January 1980 to December 2012, was performed by the first author with key words of“poly(vinyl alcohol), composite material, tissue engineering scaffold”both in Chinese and English. Literatures concerning polyvinyl alcohol and its composite materials in bone, cartilage, skin, vessels and other tissue engineering scaffolds were included, and repetitive research was excluded. RESULTS AND CONCLUSION:Although there are not enough strength, complications and other shortcomings in vivo, due to its good biocompatibility and biodegradable properties, polyvinyl alcohol and its composite materials have made great progress in tissue engineering applications from the laboratory to the pre-clinical research. But its long-term effects need further research. It wil be a main research aim of scaffold materials in the future to improve the interaction of cel s with the scaffold materials by surface modification, to prepare biomimetic materials by cel microenvironment simulation, to improve the hydrophilicity, the adhesion of cel s, and cel differentiation and proliferation, to bionic the structure and function of the natural extracel ular matrix by building three-dimensional porous structure and control ing the release of cel growth factors, to meet the need of tissue regeneration by congruity or harmony of degradation and mechanical strength.