翻译英文.docx

1、翻译英文The preparation method of 3 d porous scaffold tissue engineering and technical progress吴林波，丁建东Fudan university of polymer science, polymer molecular engineering of ministry of education key laboratory of ShanghaiAbstract: one of the key technology of tissue engineering is to have good biocompati

2、bility and biodegradation absorption performance of biomaterials preparation into connected with a specific shape and pore structure of three-dimensional porous scaffolds, extracellular matrix substitution). This paper focuses on porous scaffolds preparation methods respectively and porous scaffold

3、pore structure and shape of the inner link, from two levels to hole and shape forming on tissue engineering porous scaffolds preparation methods and technologies of recent research progress are reviewed.Key words: tissue engineering; Porous scaffolds; Biomedical materials; Biodegradable polymerTissu

4、e engineering is the basic principle and method of the in vitro culture and amplification of the normal tissue cells grow to have good biocompatibility and can be gradually degraded in the body to absorb on tissue engineering porous scaffolds, form a cell? Scaffolds, cell proliferation and different

5、iation on the holder, and then implanted tissue damage to the complex parts, continue to proliferation and secretion of extracellular matrix in the body, with the gradual degradation of the material, form new compatible with its function and form of tissue or organs, so as to achieve the purpose of

6、repairing damage to tissues or organs. This method will make tissue defect treatment from a new era of organ transplant organs into manufacturing.polymers. As an effective cells scaffold, material itself is not enough. One of the key technology of tissue engineering is the biological materials with

7、a certain shape and pore structure of three-dimensional porous scaffolds. There have been many articles on tissue engineering porous scaffolds, the preparation methods are introduced and reviewed, but focuses on the hole method and the bracket hole structure, rarely involve stent appearance molding

8、method. This paper focuses on porous scaffold pore structure and shape and the preparation method of inner link, according to our understanding of the resulting from the hole and shape forming two levels on tissue engineering porous scaffolds preparation methods and technology systematically summari

9、zed, classified and analyzed.1. The preparation of tissue engineering scaffolds requirement and structure levelPorous scaffolds in tissue engineering have the effect of extracellular matrix, is a bionic structure and function of extracellular matrix. In addition to the inject able materials, most of

10、 the tissue engineering bracket must be made into porous scaffolds in advance. This review focuses on porous scaffolds. Porous tissue engineering scaffold need to meet the following requirements: Good biocompatibility, which has no obvious cytotoxicity, inflammation and immune rejection; Suitable bi

11、odegradable absorbent, which corresponds to a cell, tissue growth rate of the degradation of the absorption rate. Suitable pore size, high porosity and connected pore configuration, to facilitate the cultivation of a large number of cells, the growth of cells and tissues, the formation of extracellu

12、lar matrix, transport of oxygen and nutrients, metabolites of excretion and the blood vessels and nerves of the growth; Specific 3 d shape to obtain the required shape of tissues or organs; High surface area and surface physical and chemical properties appropriate for cell adhesion, proliferation an

13、d differentiation, as well as the load growth factors such as biological signaling molecules; Match the mechanical properties of embedded parts structure strength, and micro environment in vivo biomechanics to maintain structural stability and integrity, as well as implanted cells improve suitable m

14、icro stress environment.Porous scaffold tissue engineering level of pore structure has four size: anatomical shape and size, big pore size, the size of the hole wall, internal fine structure size of hole wall. Look from the preparation, large hole size, hole size, hole wall inner micro structure dep

15、ends on the hole method, and the anatomic shape and size depends on the molding method. Therefore, the preparation of tissue engineering scaffolds are usually divided into holes and shape forming two levels, both is essential, together to meet the requirements of system support. Therefore, tissue en

16、gineering, the preparation of porous scaffolds is there are two main problems need to solve, namely get connected to the porous structure and the right shape.2. The porous scaffold of tissue engineering to hole method and technologyPorous scaffold of tissue engineering hole shape is mainly connected

17、 with porous sponge or foam, fiber, tubular structure, etc. Three, accordingly, the hole method and technology is also each are not identical.2.1fiber scaffoldsTissue engineering scaffolds is first used in the study of one of substitute of extracellular matrix, mainly by the PGA or its copolymer and

18、 other crystalline polymer fibers. Coated fabric to fabric heat treatment or use or solution method, can make the physical link is formed between adjacent fibers, so that the fiber scaffold stability, withstand voltage. Fiber scaffold by using cavity die easily made into various shapes, have been su

19、ccessfully used in cartilage and other field of tissue engineering. Lack of scaffolds in porosity and pore size is not easy to control, also not easy to separate regulation.2.2 porous foam or sponge scaffoldPorous foam or sponge scaffold to hole methods mainly include particle induced hole method, t

20、he thermal induced phase separation, gas foaming and sintered microsphere method, etc.2.2.1 particle hole methodParticle hole method refers to the first tissue engineering materials and hole agent made uniform mixture of particles, and then use the different solubility or volatile, will cause the po

21、re particle removal, occupied space into pores and particles. Particles can cause hole agent with sodium chloride, sodium citrate and sodium tartrate water soluble inorganic salt or sugar particles, paraffin or ice particles is also available. The most commonly used method is to use inorganic salt s

22、oluble in water and insoluble in organic solvents, polymers, soluble in organic solvent and insoluble in water, the polymer solution by solvent casting method/sand pouring the mixture into a membrane, and then leaching particle porous scaffolds. The law is often referred to as solvent casting/partic

23、ulate leaching 4 method, modified by Mikos etc as a fiber link method, solvent casting/particulate leaching of porous scaffolds prepared by easy to form a dense layer, when if cast after vibration unceasingly to most of solvent evaporation, and can prevent the particle sedimentation, inhibit the for

24、mation of surface layer.Particles to hole method is simple, wide applicability, easy independent regulation, porosity and pore size is a generic method, has been widely used, but to hole when often need to organic solvents.2.2.2 phase separation/freeze drying Was used to prepare porous scaffold of t

25、issue engineering phase separation refers to the polymer solution, emulsion, or hydromel at low temperature freezing, frozen in the process of phase separation, forming rich solvent phase and polymer phase, and then by freeze drying method to remove solvent to form a porous structure. Therefore, pha

26、se separation and often referred to as the freeze-drying method, according to the system configuration can be simply divided into different emulsion freeze-drying method of freeze drying method, solution and water gel freeze drying.Whang etc will first emulsion freeze-drying method used in the prepa

27、ration of tissue engineering porous scaffolds. Will water with polymer solution homogenization is water-in-oil emulsion, and casting into the mould, freeze-drying removal water and solvent, porous scaffolds. Solvent evaporation will shape connected to the pore structure of pore surface area. Pore st

28、ructures were the main influencing factors of oil-water ratio, polymer molecular weight. The method to avoid the high temperature, which is beneficial to growth factor biological active molecules such as proteins or differentiation factor is introduced and control release, large specific surface are

29、a, easy to operate, but the small hole size.Solution freeze drying method for preparation of porous scaffolds, the scaffold holes tend to be small size, Nam by freezing process parameter control and the preparation of the hole size more than bold effect using porous scaffolds, found the hole size we

30、re the main influencing factors of solution concentration, freezing rate and frozen temperature gradient, etc.The gelatin and alginate and chitosan hydrogel by freeze drying can also be made porous scaffolds. Hydrophilic hydrogel porous scaffolds in fluid strength degradation in the environment is a

31、 worthy problem, usually need to composite with other materials. Phase separation often freeze drying hole size slants small, but the law to avoid the high temperature, thus got the attention of the researchers.3. The engineering porous scaffolds shape forming methods and technologiesTissue engineer

32、ing porous scaffolds preparation methods and technology, the more committed to hole method and pore structure, and concerned about the bracket shape forming method is relatively small, reported in the literature to film, cylindrical, cube stents in simple shapes. And more application in tissue engin

33、eering is to match a specific tissue or organ has complicated shape of 3 d porous scaffolds, and stent shape forming methods and technologies is also an important aspect of the preparation of porous scaffolds.Generally, the porous scaffolds appearance molding methods are mainly manual molding and mold design. Particle leaching solvent casting m