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Cutaneous chronic wounds are a major global health burden in continuous growth due to population aging and the higher incidence of chronic diseases, such as diabetes. In the process of spontaneous wound healing, growth factors play a vital role. Thanks to the high content of growth factors in platelet rich plasma(PRP), more and more PRP has been used to treat chronic refractory wounds, including diabetic ulcer, pressure ulcer, venous ulcer, and burns, etc., and has achieved significant results. Given the short duration of local growth factor release in the wound when PRP is applied alone, some studies have combined PRP with different tissue biology materials, such as hyaluronic acid, chitosan, and chitosan derivatives, to achieve better therapeutic results. In this paper, the preparation method of PRP, the mechanism of growth factors, the effect of PRP on wound repair, the combined application of PRP with repair materials and the advantages and disadvantages of PRP are reviewed.
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BACKGROUND: Bioabsorbable materials have shown obvious advantages in clinical application for more than ten years, and have been widely used in many biomedical fields. OBJECTIVE: To review characteristics of bioabsorbable materials and their application in orthopedics. METHODS: The articles published in Wanfang, CNKI, VIP, and PubMed databases were searched by computer. The key words were “bioabsorbable materials, bioabsorbable metal materials, bioabsorbable inorganic materials, polymer materials, biocomposites” in Chinese, and “bioabsorbable/bioabsorbable material, metal material, polymer material, biocomposites” in English. RESULTS AND CONCLUSION: Absorbable metal materials have good mechanical properties. The corrosion mechanism of polymer materials is clear, which can predict the corrosion behavior and corrosion rate in vivo and in vitro, but its load-bearing performance is not as good as that of absorbable metal materials. After certain treatment, bioceramics have good biocompatibility, bone conductivity and osseointegration, but they are brittle and difficult to be formed. Biocomposites have the properties of component materials, and can also obtain new properties that single component materials do not have, so it has a wide application prospect.
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BACKGROUND: Graphene-related materials have good biocompatibility and can improve cartilage repair. At the same time, their excellent mechanical strength and electrical conductivity make them promising as cartilage replacement materials, which have been widely used in tissue engineering. OBJECTIVE: To review the general properties, biocompatibility and application of graphene in cartilage tissue engineering and cartilage repair. METHODS: A computer-based online search of CNKI and PubMed databases was performed using the search terms “graphene, tissue engineering, biocompatibility, cartilage” in Chinese and English to search related literatures published between January 2000 and January 2019. Preliminary screening was conducted by reading the titles and abstracts to exclude the literature irrelevant to the theme of the paper. According to inclusion and exclusion criteria, 67 literatures were included in the final analysis. RESULTS AND CONCLUSION: Graphene has good biocompatibility, and has low cytotoxicity to prokaryotic cells and eukaryotic cells, but the cytotoxicity can be further reduced by chemical modification or surface modification, so as not to affect the growth of cells. Graphene and its derivatives can promote the growth and chondrogenic differentiation of human bone marrow mesenchymal stem cells, as well as the proliferation and maturation of chondrocytes, and accelerate the repair of cartilage defects. Due to its mechanical strength and electrical conductivity, graphene can compound biomimetic cartilage material, which is suitable for cartilage tissue engineering. Graphene has several unresolved problems and challenges, but the application potential of graphene-related materials may pave the way for future breakthroughs in tissue engineering research.
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BACKGROUND: Combining drugs with materials using 3D printing technology can be formulated Into a dosage form with a specific release rate, which is better for clinical use. OBJECTIVE: To review the preparation technique, advantages and indications of pharmaceutical composites made from western medicine, traditional Chinese medicine, metal elements and Ions and related materials. METHODS: The first author used the search terms "Drug; Chinese medicine; Metal; Composite materials; 3D printing" to search the CNKI and Wanfang databases In Chinese and the PubMed and Web of Science in English to retrieve papers published during 1950-2019. A total of 339 papers were preliminarily retrieved. After screening, 46 papers were included in the final analysis. RESULTS AND CONCLUSION: Pharmaceutical composite materials made of western medicine, traditional Chinese medicine, metal elements and Ions and related materials have certain advantages in the pharmaceutical field and clinical use. It can not only improve the bioavailability of drugs, reduce toxic side effects, but also achieve a combination of drugs. In recent years, drug composite materials have been used In orthopedics, dentistry, cardiovascular medicine, otolaryngology and other fields, but its application is still in its Infancy. Many aspects need to be Improved, such as improving the quality of drug composites, Increasing mechanical stability, reducing the brittleness, printing the full-featured blood vessels and organs that fit the size of the human body, and better Imitating the biomechanics and tissue structure of human body.
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BACKGROUND: Polyetheretherketone (PEEK) and Its composites have a unique set of properties, and 3D printing technology can customize personalized Implants according to the patient's condition, and the effective combination of the two plays a significant role In the field of bone repair. OBJECTIVE: To summarize the application status of PEEK and Its composite combined with 3D printing technology In the field of bone repair, and to further predict the application prospects of the effective combination of the two. METHODS: CNKI, PubMed, and Web of Science databases were retrieved with the search terms “PEEK, PEEK composites, bone defect repair, PEEK Implants, PEEK 3D printing, prosthodontlcs” in English and Chinese, respectively, for the articles published from April 1995 to April 2019. Totally 147 articles were searched, and finally 51 eligible articles were enrolled for review in accordance with the inclusion and exclusion criteria. RESULTS AND CONCLUSION: Biologically active materials and the particles or fibers with Improved mechanical properties were Introduced Into the PEEK matrix to prepare its composite. 3D printing technology was used to precisely customize Implants that are highly matched to the patient's defect. The Implants with good biocompatibility, bioactlvity, and mechanical properties exhibited good therapeutic effects In the repair of skull, jaw, spine, lumbar vertebra, artificial joint and oral defects. They Improved patient satisfaction after treatment. This article summarized the application of PEEK, its composite and 3D printing technology In the repair of various bone defects, and expressed its views on the application and prospect of personalized PEEK implants or prostheses prepared with 3D printing technology.
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BACKGROUND: Dentin particles, tricalcium phosphate/collagen protein composites and Bio-oss particles can repair jaw defects, but the excellent osteogenic effect is not clear. OBJECTIVE: To compare osteogenic effects of three different bone graft materials on mandibular defects in beagle dogs. METHODS: Eight 1-year-old beagles were selected. A boxed bone defect area of 10 mm × 8 mm × 2 mm was prepared at the bilateral mandibular external oblique line and randomly divided into four groups with four bone defect models in each group. Undemineralized dentin particles were implanted in group A; tricalcium phosphate/ collagen protein composite materials were implanted in group B; Bio-oss particles were implanted in group C; and group D was used as blank control. Three months after transplantation, the samples were taken for histological observation. The experimental animals were approved by the Ethics Committee of the Experimental Animal Center of Dalian Medical University. RESULTS AND CONCLUSION: (1) In group A, dentin particles were slightly absorbed, surrounded by new bone tissue; new bone trabeculae and capillaries could be seen, and a large number of fibrous connective tissue surrounded dentin particles in the central area of bone graft. In group B, a small number of new bone trabeculae and osteoblasts could be seen; a large number of powdered β-tricalcium phosphate particles and a small amount of inflammatory cells could be seen in the fibrous connective tissue; and some β-tricalcium phosphate particles were surrounded by new bone tissue. Bone marrow cavity could be seen in the new bone. In group C, some Bio-oss particles were surrounded by new bone tissue; some Bio-oss particles were wrapped by surrounding fibrous connective tissue, and fibers, particles and new bone were intertwined. There was no new bone formation in group D, and many capillaries could be seen in a large number of fibrous connective tissue. (2) The rate of new bone formation in groups A, B and C was higher than that in group D (P < 0.05); the rate in groups A and C was higher than that in group B (P < 0.05). (3) The results show that all the three kinds of bone graft materials can promote the formation of new bone. The short-term osteogenic effects of undecalcified xenogeneic dentin particles and Bio-oss particles are better than tricalcium phosphate/collagen protein composites, but the long-term effects need to be further observed.
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BACKGROUND: Poly(glycerol sebacate) holds excellent and good biocompatibility, flexibility and degradability, which is widely used in soft tissue replacement and tissue engineering, drug delivery carrier, wound dressing, and bone-cartilage regeneration. OBJECTIVE: To summarize the research progress in the optimal synthesis and medical application of poly(glycerol sebacate) and its composites. METHODS: PubMed, Elsevier, CNKI and WanFang databases were retrieved. The key words were “poly(glycerol sebacate), synthesis, cardiac muscle, blood vessels, nerves, skin, drug delivery carrier, wound dressing, bone regeneration” in English and Chinese, respectively. Finally, 43 articles eligible for the inclusion criteria were obtained. RESULTS AND CONCLUSION: In recent years, poly(glycerol sebacate) has attracted much attention because of its many excellent properties. Many basic scientific studies and animal experiments have confirmed that it is suitable for tissue engineering. Conventional poly(glycerol sebacate) curing process requires high temperature, high vacuum and long duration, which prevents the polymer from binding directly to cells or temperature-sensitive molecules, resulting in some limitations in its application. The composite scaffold material synthesized with a variety of other materials can make up for the corresponding shortcomings of its application in myocardial and vascular tissue engineering, drug delivery carrier, nerve guiding materials, skin and wound dressing, and bone-cartilage tissue engineering. At present, most of the studies on poly(glycerol sebacate) composites focus on the cytobiology level, and few studies focus on the mechanism of action in vivo. Further study may develop an important material for tissue replacement.
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BACKGROUND: Currently, surgical treatment for acetabular labrum injury includes debridement, repair, refixation and acetabular labrum reconstruction. Labrum reconstruction is a newly developed surgical method, which uses autograft or allograft to repair labrum defect. At present, there are many options for graft repair, and the recent follow-up shows that this method can well restore the structure and function of the labrum, and hascertain advantages over debridement, excision, and repair. However, no study has shown the long-term effect of reconstruction, and which situation and which graft are more suitable. OBJECTIVE: To review graft selection of acetabular labrum reconstruction under arthroscopy. METHODS: PubMed and GeenMedica databases were retrieved for studies on acetabular labrum reconstruction published from 2000 to 2019, especially in the past 10 years. The key words were “labrum, reconstruction, graft, hip, acetabulum”. RESULTS AND CONCLUSION: (1) There are a number of options for graft repair, including autograft (iliotibial band, gracilis and semitendinosus, quadriceps tendon, rectus femoris tendon, joint capsule) and allograft (peroneus brevis, tensor fascia lata). Recent follow-up shows that these grafts can restore labrum structures and hip movement. (2) However, as an emerging surgical procedure, there is currently a lack of long-term follow-up and prospective comparative studies to prove the long-term effects of reconstruction and prove which grafts are more suitable in which conditions. (3) In future studies, we need to compare the medium and long-term efficacy of different grafts for clinical selection. With the development of science and technology, the problem of artificial composite materials has been solved, and will become a more promising alternative.
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BACKGROUND: Hydroxyapatite has been widely used in the studies on bone materials due to its good histocompatibility and bone conductivity. But pure hydroxyapatite has no antibacterial properties. Therefore, the antibacterial modification of hydroxyapatite is of great importance.OBJECTIVE: To review the research progress of the antibacterial modification of hydroxyapatite. METHODS: A computer-based retrieval of Science Direct online, PubMed, and CNKI databases was performed for the articles published before 2019. The key words were “antibacterial mechanism, hydroxyapatite, silver, gold, copper, cobalt, chitosan, strontium, zinc, gallium, magnesium, selenium, titanium” in English and Chinese, respectively. The irrelevant, repeated and old articles were excluded. RESULTS AND CONCLUSION: There are many ways to modify hydroxyapatite, but the main way is to add metal antibacterial particles. Silver, gold, copper, cobalt, chitosan, strontium, zinc, gallium, magnesium, selenium and titanium can be added into hydroxyapatite to make it have antibacterial activity. There are still some limitations in the research of antibacterial materials: the release curve of antibacterial Ions in hydroxyapatite has not been well regulated. There are few antibacterial materials, let alone used for implants in vivo. More nontoxic substances with good antibacterial properties need to be found. Due to the toxicity of antibacterial Ions, there is no uniform standard for the optimal concentration of each kind of antibacterial ion.
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Chitosan(CS)is the product of chitin derived by removal of some acetyl groups, which is non-toxic, safe and biodegradable. It is easily obtainable and has wide application prospects. However, due to its intramolecular hydrogen bonding and spatial configuration of macromolecules, CS is not easily soluble in water and organic solvents, so its application is limited. For its extended application, CS is often modified or compounded with other materials. This article briefly summarizes the modification methods of CS, including acylation, etherification, alkylation, quaternization, graft copolymerization, etc., and introduces the application of CS composite materials in hemostasis.
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El objetivo de este estudio fue analizar el comportamiento, contracción volumétrica, de diferentes resinas compuestas de fotopolimerización, expuestas a variadas condiciones de incidencia lumínica. Se tomaron volúmenes estandarizados de 7 resinas compuestas (microhíbridas y nanohíbridas y nanoparticulados) que se colocaron sobre una línea de referencia en portaobjetos, cubriéndose luego con otro y aplicando una fuerza previamente establecida. Se midió luego con un calibre electrónico la variaciones en el diámetro de la muestra bajo tres situaciones diferentes: luz ambiente (natural), luz foco (halógena), luz artificial (tubos fluorescentes) y sus combinaciones. Resultados: Se observó la mayor variación porcentual al exponer a las muestras simultáneamente a la luz ambiente, artificial y operatoria, siendo los valores más altos de reducción para las resinas compuestas Brilliant NG Coltene (Dentina) y Miris 2 Coltene (Dentina) con -2.52% y -2.7% respectivamente. Conclusión: existieron modificaciones en el volumen de todos los materiales expuestos a las diferentes condiciones de luz y tiempo de exposición. Comparando los resultados con el estudio previo (2007) se pude inferir que los materiales usados en el presente estudio resultaron más fotosensibles, dado que a similar exposición, aumentaron y/redujeron su tamaño en mayor medida (AU)
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Composite Resins/chemistry , Curing Lights, Dental , Polymerization , Time Factors , Materials Testing , Analysis of Variance , Dentin , LightABSTRACT
The paper retrieved the literature information on the artificial bone and composite artificial bone in CNKI, Wanfang data and foreign databases such as Pubmed and SCI-E from 2009 to 2016, and summarized the characteristics and deficiency of all kinds of artificial bone materials.On this basis, it briefly described the functional application and the principles of the composite artificial bone repair materials, and introduced the application of tissue engineering and 3D printing technology in the field, which could provide reference for the exploration of new types of composite artificial bone repair materials.
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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.
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A rigorous microscale electrokinetic model for hydrogel-colloid composites is adopted to compute macroscale profiles of electrolyte concentration, electrostatic potential, and hydrostatic pressure across membranes that separate electrolytes with different concentrations. The membranes are uncharged polymeric hydrogels in which charged spherical colloidal particles are immobilized and randomly dispersed with a low solid volume fraction. Bulk membrane characteristics and performance are calculated from a continuum microscale electrokinetic model (Hill 2006b, c). The computations undertaken in this paper quantify the streaming and membrane potentials. For the membrane potential, increasing the volume fraction of negatively charged inclusions decreases the differential electrostatic potential across the membrane under conditions where there is zero convective flow and zero electrical current. With low electrolyte concentration and highly charged nanoparticles, the membrane potential is very sensitive to the particle volume fraction. Accordingly, the membrane potential - and changes brought about by the inclusion size, charge and concentration - could be a useful experimental diagnostic to complement more recent applications of the microscale electrokinetic model for electrical microrheology and electroacoustics (Hill and Ostoja-Starzewski 2008, Wang and Hill 2008).
Um modelo eletrocinético rigoroso para compósitos formados por um hidrogel e um colóide é adotado para computar os perfis macroscópicos de concentração eletrolítica, potencial eletrostático e pressão hidrostática através de uma membrana que separa soluções com diferentes concentrações eletrolíticas. A membrana é composta por um hidrogel polimérico sem carga elétrica onde partículas esféricas são imobilizadas e dispersas aleatoriamente com baixa fração de volume do sólido. As características da membrana e a sua performance são calculadas a partir de um modelo eletrocinético de contínuo microscópico (Hill 2006b, c). As computações realizadas neste artigo quantificam os potenciais de corrente e de membrana. Para o potencial de membrana, aumentando a fração de volume das inclusões carregadas negativamente diminui o diferencial do potencial eletrostático através da membrana sob condições de fluxo convectivo e corrente elétrica nulos. Para concentrações eletrolíticas baixas o potencial de membrana torna-se muito sensível à fração de volume das partículas. De maneira similar, o potencial de membrana e as cargas elétricas trazidos pelo tamanho da inclusão, carga e concentração podem prover um diagnóstico experimental útil para complementar aplicações mais recentes do modelo eletrocinético microscópico em eletroacústica e eletro-micro-reologia (Hill and Ostoja-Starzewski 2008, Wang and Hill 2008).
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Objective Prepare biomimetic multilayered scaffold which has similar structure of natural cartilage. Methods By lyophilizing the scaffolds which were prefrozen at -20℃ and in liquid nitrogen successively, we prepared double-layered spongy scaffolds. By partially thawing the prefrozen samples and refreezing them in liquid nitrogen before the final liyophilization, we prepared biomimetic multilayered scaffolds. XRD and FT-IR were used to confirm the interaction between collagen and chitosan. SEM was used to observe the morphologies of the scaffolds. The mechanical properties of pure chitosan scaffolds, pure collagen scaffolds, composite single-layered scaffolds and biomimetic multilayered scaffolds were compared. Results There is chemical interaction between collagen and chitosan. Composite materials eill form better pore structure. The biomimetic multilayered scaffolds had upright pores, round pores and a dense layer from bottom to top of the scaffolds. The scaffolds had quite different mechanical properties between dry and wet state. Under wet state, the different layers of the biomimetic multilayered scaffolds have different mechanical properties. Conclusions The biomimetic structure of the multilayered scaffold is very close to that of the natural articular cartilage, and the different layers of the biomimetic multilayered scaffolds had different mechanical properties under wet state. These are hopefully beneficial to help maintain the phenotypes of chondrocytes and promote the repairing effect of cartilage defects .
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Objective Prepare biomimetic muitilayered scaffold which has similar structure of natural cartilage.Method By lyophilizing the scaffolds which were prefrozen at-20℃ and in liquid nitrogen successively,we prepared double-layered spongy scaffolds.By partially thawing the prefrozen samples and refreezing them in liquid nitrogen before the final liyophilization,we prepared biomimetic multilayered scaffolds with about 2mm thickness.XRD and FT-IR were used to confirm the interaction between collagen and chitosan.SEM was used to observe the morphologies of the scaffolds.The mechanical properties of pure chitosan scaffolds,pure collagen scaffolds,composite single-layered scaffolds and biomimetic multilayered scaffolds were compared both in dry and wet conditions.Results There was chemical interaction between collagen and chitosan.Composite materials will form better pore structure.The biomimetic multilayered scaffolds have upright pores,round pores and a dense layer from bottom to top of the scaffolds.The scaffolds have quite different mechanical properties between dry and wet state.Under wet state,the different layers of the biomimetic muitilayered scaffold have different mechanical properties.Results The biomimetic structure of the multilayered scaffold is very close to that of the natural articular cartilage,and the different layers of the biomimetic muitilayered scaffold had different mechanical properties under wet state.These are hopefully beneficial to help maintain the phenotypes of chondrocytes and promote the repairing effect of cartilage defects.
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Objective Prepare biomimetic muitilayered scaffold which has similar structure of natural cartilage.Method By lyophilizing the scaffolds which were prefrozen at-20℃ and in liquid nitrogen successively,we prepared double-layered spongy scaffolds.By partially thawing the prefrozen samples and refreezing them in liquid nitrogen before the final liyophilization,we prepared biomimetic multilayered scaffolds with about 2mm thickness.XRD and FT-IR were used to confirm the interaction between collagen and chitosan.SEM was used to observe the morphologies of the scaffolds.The mechanical properties of pure chitosan scaffolds,pure collagen scaffolds,composite single-layered scaffolds and biomimetic multilayered scaffolds were compared both in dry and wet conditions.Results There was chemical interaction between collagen and chitosan.Composite materials will form better pore structure.The biomimetic multilayered scaffolds have upright pores,round pores and a dense layer from bottom to top of the scaffolds.The scaffolds have quite different mechanical properties between dry and wet state.Under wet state,the different layers of the biomimetic muitilayered scaffold have different mechanical properties.Results The biomimetic structure of the multilayered scaffold is very close to that of the natural articular cartilage,and the different layers of the biomimetic muitilayered scaffold had different mechanical properties under wet state.These are hopefully beneficial to help maintain the phenotypes of chondrocytes and promote the repairing effect of cartilage defects.
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Objective Prepare biomimetic muitilayered scaffold which has similar structure of natural cartilage.Method By lyophilizing the scaffolds which were prefrozen at-20℃ and in liquid nitrogen successively,we prepared double-layered spongy scaffolds.By partially thawing the prefrozen samples and refreezing them in liquid nitrogen before the final liyophilization,we prepared biomimetic multilayered scaffolds with about 2mm thickness.XRD and FT-IR were used to confirm the interaction between collagen and chitosan.SEM was used to observe the morphologies of the scaffolds.The mechanical properties of pure chitosan scaffolds,pure collagen scaffolds,composite single-layered scaffolds and biomimetic multilayered scaffolds were compared both in dry and wet conditions.Results There was chemical interaction between collagen and chitosan.Composite materials will form better pore structure.The biomimetic multilayered scaffolds have upright pores,round pores and a dense layer from bottom to top of the scaffolds.The scaffolds have quite different mechanical properties between dry and wet state.Under wet state,the different layers of the biomimetic muitilayered scaffold have different mechanical properties.Results The biomimetic structure of the multilayered scaffold is very close to that of the natural articular cartilage,and the different layers of the biomimetic muitilayered scaffold had different mechanical properties under wet state.These are hopefully beneficial to help maintain the phenotypes of chondrocytes and promote the repairing effect of cartilage defects.
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@#ObjectiveTo approach the taxonomy of polymer hydrogels prepared with composite material science methods.MethodsThe research results which have been obtained were synthesized and analysed in the light of multiscale design viewpoint,and the hydrogel composite materials were classified by the composite ways and its structural levels.Results and ConclusionA kind of taxonomy system was advanced in which new concepts of intermolecular composite,textural composite etc.were induced.Apply-ing these concepts and methods will be helpful to research on composite biomaterials.
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Composite materials are widely used in various areas including medicine.They are constructed with two or above kinds of materials by using physical or chemical methods in macroscopic scale and possess new properties.Based on the characters of composite materials,several theoretical methods for studying the mechanical properties of composite materials are introduced in detail as well as their wide application in medicine.