This paper aimed to present the surface modification of tissue engineering materials and its correlation with cell compatibility from the aspects of cell-compatibility polymer surface group transformation and bioactive molecule immobilization.

AIM:To analyze the mechanism,thermadynamic theoretical basis,dynamic mechanism and influencing factors of thermally induced phase separation (TIPS)in order to completely grasp the factors affecting the size,distribution and form of pores,so that the adjusted range of pore can be widened and the preparation of Porous membrane can be repeated and controlled.METHODS: Considering from the structural characteristics of tissue engineered materials,the methods of preparing porous membrane using TIPS technique,the hermadynamic theoretical basis,dynamic mechanism and influencing factors were analyzed,the problems and investigative directions in the future were also analyzed.TIPS technique is a process of phase separation of polymer homogenous solution under quenching,and it is suitable for diameter and structural form of the micropore materials prepared using TIPS are closely correlated with the kind and dispensing proportion of polymer attrnuant,polymer concentration and polymer molecular mass,etc.conducted,including determination of polymer-solvent system phase diagram,study of form and appearance of porous membrane of different thickness,study of form and appearance of porous membrane prepared with systems of different X,which is the parameter of polymer-solvent interaction.

Surface physical chemical properties of tissue-engineered materials are greatly important for histocompatibility of the materials. Therefore, surface modification based on original physical mechanical performance could promote cell attachment and growth or bioactive molecule, and significantly improve material cell compatibility. To date, plasma and grafting has become main methods of surface modification of polymers. This paper introduced plasma and grafting methods of surface modification of materials and the application in tissue engineering.

BACKGROUND: The development of tissue engineering has provided a possibility for repairing and reconstructing tissues or organs. However, studies on biomedical tissue-engineered and polymer tissue-engineered materials need to be investigated. OBJECTIVE: To clarify the content of tissue engineering and the application of polymer material in tissue engineering from the point of biocompatibility. RETRIEVAL STRATEGY: Using the terms "tissue engineering, tissue engineering materials, Polymers materials, bio-compatibility, bio-compatibility materials, cell-compatibility, cell-compatibility materials", we retrieved PubMed database to identify studies published between January 1990 and December 2007 in the English language. At the same time, we searched Wanfang database with the same terms in the Chinese language. After primarily selected, 81literatures were kept. Inclusive criteria: studies, whose contents are related to biocompatibility of tissue-engineered materials. Exclusive criteria: repetitive studies or Meta analysis. Thirty literatures corresponded to the inclusive criteria, and fifty-one were rejected due to obsolete or repetitive contents. Among the 30 included literatures, 19 were about biocompatibility, and the remaining 11 about cellular compatibility materials. LITERATURE EVALUATION: The included studies were mainly from Pubmed database and Wanfang database. A total of 25 treatises and 5 reviews were kept. DATA SYNTHESIS: The content of tissue engineering consisted of seeded cell inoculation, biomaterial implanting and cell transplantation. Allogenic, autogenous, and xenogenous tissues were in vitro broken into cells, and then reconstructed through inoculation and proliferation by gene reconstruction technique. Much attention should be focused on how to reconstruct tissue-engineered materials with materials and living cells, I.e. To reconstruct active materials with biological functions. Tissue-engineered materials should have the best interface reaction effect between material surface and cells. Therefore, the core of studying tissue-engineered materials is to design a device, which has chemical molecular level and three-dimensional molecular level cell/material mixed surface, and also has a three-dimensional molecular level appearance corresponding to biomechanical requirement. Polymer materials have good physical mechanical functions, and their molecular structures are closer to living body. Therefore, polymer materials are widely used as biomaterials and exert an important role in the field of tissue engineering. CONCLUSION:To study biomaterials with good tissue compatibility is the basis for tissue engineering development. Polymer materials are widely used in the tissue engineering due to their good property and molecular structure closer to living body.

BACKGROUND:To clarify the effects of topology of tissue engineering material surface on cell compatibility from random roughness.porosity,groove/ridge, fiber,texture and protein tracks 6 aspects. STUDY SOURCES: Using the terms"biocompatibility,biocompatibility materials,tissue engineering,tissue engineering materials.cell-compatibility and cell-compatibility materials",we searched the PUBMED database to identify studies published in the English language from January 1987 to January 2007. STUDY SELECTION:The data were selected primarily.The quotations in each paper ware looked for.Inclusive criteria: The contents stated in papers were related with biocompatibility of tissue engineering material. Exclusive criteria: repetitive study or Meta analysis papers.DATA EXTRACTION:Totally 74 related papers were collected.Thirty-two met inclusive criteria,among which,24 related with biocompatibility and 8 related with cell-compatibility materials.The other 42 papers were excluded due to obsolete or repetitive contents. DATA SYNTHESIS:①The interaction of tissue engineering material and living body:Various Interactions producing when high polymer tissue engineering material contacts with tissue of living body are reviewed. It js pointed out that the interaction of material and living body depends on the biocompatibility degree of material;The influences of materials on histocompatibility include microscopic molecular level and macroscopic scale level,moreover,the effect of macroscopic scale level (include the topology of material surface) is more important than chemical effect of microscopic molecular level.②Effects of physical and chemical properties on cell-compatibility of materials:The effects of topology of surface of random roughness,porosity,groove/ridge,fiber, texture and protein tracks 6 kinds of materials on cell-compatibility are reviewed. It is also pointed out that the influences are very important in studying the biocompatibility of tissue engineering material and designing tissue compatibility materials.CONCLUSION:Topology of material surface has great influences on cell-compatibility of material.The interaction of cells and polymer is an index to evaluate cell-compatibility of material.Short-term interaction degree of cell and polymeric material can be assessed by detecting the adhesion degree of cells and polymeric material surface,while long-term interaction by detecting the growth of cells cultured in vitro or polymeric material implanted in vivo.

OBJECTIVE: To discuss the influence of physical and chemical properties of tissue engineered material surface on the cell compatibility, involving the surface energy, hydrophilicity/hydrophobicity, chemical structure and active factors loaded on the material surface, point out that the physical and chemical properties of material surface have great influence on the cell compatibility of the material, i.e., explain the cell compatibility of tissue engineered materials.DATA SOURCES: An online search of Pubmed database was undertaken to identify relevant articles published in English from December 1997 to December 2006 using the keywords of "bio-compatibility, bio-compatibility materials, tissue engineering, tissue engineering materials, cell-compatibility". Meanwhile, Chinese relevant articles published from December 1997 to December 2006 were searched in Wanfang database with the same keywords in Chinese.STUDY SELECTION: The data were primarily checked. Inclusive criteria: articles about tissue-engineered materials of biocompatibility. The repetitive studies or Meta analysis were excluded.DATA EXTRACTION: Totally 71 relevant literatures were collected, 33 of which were accorded with the inclusive criteria, and the 38 repetitive ones or with old contents were excluded. Of the 33 involved literatures, 22 dealt with biocompatibility, and 11 with the cell-material compatibility.DATA SYNTHESIS: ① Interaction of tissue-engineered materials with organism: The various interactions of tissue-engineered polymer materials with organism are summarized. It is pointed out that the interactions of materials with organism decide the degree of material-tissue compatibility. The effects of material on the tissue compatibility result from the micromolecular and macroscopic levels, and the chemical effect of the macroscopic level is more important than that of the micromolecular one. ② Influence of the physicochemical properties of the material surface on the cell-material com coatibility:The influences on the cell-material compatibility by the chemical nature and structure, composition, energy, hydrophilicity/hydrophobicity, charges and active factorsloaded on the surface are summarized. The obtained information is the important contents for understanding the biocompatibility of the tissue engineered materials and designing biocompatible materials. CONCLUSION: The physical and chemical properties of the material surface greatly affect the cell-material compatibility. The interaction of cells with the polymer matrix is an index to evaluate the cell compatibility. The degree of the short-term interaction of cells with polymer materials can be evaluated by the degree of adhesion on the surface of the polymer materials, while the long-term interaction can be evaluated by detecting the growth of cells cultured in vitro or implanting the polymer material.

OBJECTIVE: Based on the mechanism of cellular adhesive growth and the developing course of cell compatibility materials, the cytological effects of tissue engineering materials of various polymers and surface topographies are reviewed. And presume theoretically that the materials of porous structure are better than smooth materials in surface, and biodegradation materials can explain the biocompatibility.DATA SOURCES: An online search was conducted in PUBMEDdatabase to identify the related articles published from December 1997 to December 2003 with the key words of "tissue engineering, tissue engineering materials, cell-compatibility, cell compatibility materials, procession anchorage", and the language was limited to English. Meanwhile, the related Chinese articles were retrieved in Wanfang database published at the same period by inputting the key words of "tissue engineering, tissue engineering materials, cell-compatibility, cell compatibility materials,mechanism of adhesive growth" into computer.STUDY SELECTION: All the data were checked primarily, and the quotations of each article were looked up. Inclusive criterion: content related to the cell-compatibility of tissue engineering materials. Exclusion criterion:repeated study or Meta-analysis.DATA EXTRACTION: Totally 41 articles were collected, and 28 ones were deleted due to the repeated or dated contents. Among the 13 articles met the inclusive criterion, 2 ones were about the mechanism of cellular adhesive growth and 11 ones were referred to the cell compatibility materials.DATA SYNTHESIS: ①The mechanism of cellular adhesive growth: To summarize the characteristics of adhesive growth in various in vitro cultured cells, and briefly describe the growth procedure of those cells cultured on substrate materials. Suggesting that compensate for the adverse effects caused by pore space structure, more effective methods should be adopted to form the transition layer of cell compatibility when the cells are required to grow.②Cell compatibility materials: To summarize the cytological effect produced by the materials of various polymers and surface topographies, and point out that the interaction mechanism between cells and materials of different surface topographies is still a difficult but valuable topic in the related fields. The physical and chemical properties as well as topological structure of the materials surface influence on the cell compati bility of materials. The interaction between cells andpolymers is the evalu ation indicator of cell compatibility of materials. The temporary interaction can be evaluated by the adhesion of cells to polymers surface, while the long-term interaction may be estimated by the growth of in vitro cultured cells or in vivo implanted polymers.CONCLUSION: Theoretically, porous materials show great superiority compared with smooth surface materials; Biodegradation materials can tackle the biocompatibility completely.

After 45 min ligation of the gerbils' bilateral carotid arteries and then 24h reperfusion,the effects of water soluble Pollen flavone element from buckwheat, Isocorydine on the stroke index of 45 min cerebral ischemia followed by reperfusion 6h and the mortality of reperfusion 24h were evaluated .The results indicated that pollen element from buckwheat could decrease the stroke index and mortality rate dramatically, while Isocorydine had no effects.It was speculated that the beneficial effects of pollen element from buckwheat on cerebral damage following ischemia with reperfusion might be due to its depressing effect on the metabolism of free radicals.

By 45 min ligation of the gerbils' bilateral carotid arteries and then 24h reperfusion, the effects of panax notogniseng saponins ( PNS ) and SOD on the stroke index of 45 min cerebral ischemia followed by reperfusion 24h were evaluated. The results indicated that PNS and SOD could decrease the stroke index and mortality dramatically.We speculated that the beneficial effect of PNS on cerebral damage folio-wing ischemia with reperfusion might be due to anti-free radical action. The effects of PNS, Rb1 Rg1 and nimodi-pine on focal cerebral ischemia were studied by 12h occlusion of middle cerebral artery in squirrel monkeys. Both Rb1 and nimodipi-ne alleviated the brain edema and calcium content in ischemic tissue significantly, and reduced the infarcted size, while the effect of Rg1 was not statistical. The results suggested that the anti-cerebral ischemia effect of Saponin Rb1 probably contributes to its calcium antagonism.

Acute in-complete cerebral ischemia were induced in 39 rabbits by hypotension coupled with hypoperfusion for 60 min, and acute forebrain ischemia were induced in other 15 rabbits by 4A-Occlus-ion for 30 min followed by reperfusion 120 min. At the end of experiment, EEG, the tissue contents of sodium,potassium and water in the cerebral cortex, the activities of LDH and CPK in the cerebral venous blood and the maximal bleeding volume were estimated. Sanchinoside D1 ( 50mg/kg, i.v.) could ameliorate significantly all the changes of relevant parameters mentioned above in model animals. It was suggested that Sanchinoside D1 had some protective effect on acute cerebral ischemia in rabbits