共查询到20条相似文献,搜索用时 0 毫秒
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H. L. Khor K. W. Ng J. T. Schantz Toan-Thang Phan T. C. Lim S. H. Teoh D. W. Hutmacher 《Materials science & engineering. C, Materials for biological applications》2002,20(1-2)
A preliminary cell culture study of human keratinocytes (HK) on solvent-cast and biaxially stretched poly(-caprolactone) (PCL) films was carried out. Cell attachment and proliferation on solvent-cast films was compared with commercially available wound dressings while cell attachment, proliferation and viability on biaxially stretched films were assessed using light, confocal laser and scanning electron microscopy (CLM and SEM). Solvent-cast sheets were biaxially stretched to produce 5–15-μm-thick films. Biaxially stretched films were shown to be better epidermal substrates due to the better flexibility and strength to mass ratio than solvent-cast sheets. Images obtained showed that the cells attached and proliferated on poly(-caprolactone) films, and maintained high percentage of viability throughout the culture period. Keratinocytes exhibited healthy cobblestone morphology and proliferated as continuous monolayers. These results indicated that poly(-caprolactone) films would support the attachment and proliferation of human keratinocytes and have the potential to be applied as a matrix material for tissue engineering an epidermal equivalent. 相似文献
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S. Ghosh J.C. Viana R.L. Reis J.F. Mano 《Materials science & engineering. C, Materials for biological applications》2008,28(1):80-86
Articular cartilage has a limited capacity to repair itself, and conventional therapeutic approaches have shown to have limited success as they are deficient and inconsistent in long-term repair. Tissue engineering has shown to be an alternative route to regenerate articular defects. In this work, new bi-layered scaffolds are developed in order to enhance the integration between the engineered cartilage tissue and the corresponding subchondral bone. The concept includes the use of a common polymer in both sides, poly(l-lactic acid), PLLA, to increase the bonding between them, and the use of compression moulding followed by particle leaching to process porous scaffolds with controllable porosities. A compact layer could be observed between the two layers that could be useful for independent cell culturing of the developed osteochondral constructs. A blend of starch and PLLA was used in the cartilage side, which was found to possess adequate hydration capability. For the bone region, where more stiffness and strength was required, PLLA reinforced with hydroxyapatite was used. Preliminary bioactivity tests demonstrated that the bone-layer could induce the formation of a calcium–phosphate layer in vitro, whereas the cartilage layer does not exhibit the ability for calcification. 相似文献
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Collagen as an important extra-cellular matrix (ECM) in many tissues is weakly antigenic and the structure of collagen sponges is highly porous with interconnected pores effective for cell infiltration and mass transfer of oxygen and nutrients. Its application as a scaffold is limited by poor mechanical strength and rapid biodegradation. In this paper, we attempt to graft hydrolyzed PLGA fiber surfaces with collagen by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) in combination with N-hydroxysuccinimide (NHS), and then embed these collagen-grafted PLGA fibers in collagen sponge to form a hybrid PLGA-collagen scaffold. For further stability, we cross-linked the collagen in the scaffold and used it in rat liver cell cultivation. The scaffold was characterized by mechanical micro-tester, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results showed that (1) the scaffolds exhibited isotropic and interconnected porous structure; (2) the compression modulus of this scaffold was enhanced 50 fold compared to the collagen scaffolds. The cell attachment and cytotoxicity of this scaffold were studied. Cell attachment was improved remarkably and the cytotoxicity of the hybrid PLGA-collagen scaffold was lower than that of the un-grafted PLGA-collagen scaffolds using alamarBlue™ assay normalized to the DNA content in each scaffold. This new hybrid scaffold has potential applications for tissue engineering. 相似文献
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《Virtual and Physical Prototyping》2013,8(4):275-285
Porous scaffolds are biocompatible and bioactive temporary substrates. They should present appropriated microstructure, mechanical properties and surface properties for guiding bone tissue regeneration. In this work, scaffolds of Poly(3-hydroxybutyrate) (PHB) were printed by Selective Laser Sintering (SLS). The effect of scan spacing (SS) and powder layer thickness (PLT) on the morphology, mechanical properties and dimensional deviations related to the digital model of sintered scaffolds was evaluated. Curling was observed in the first built layers of scaffolds, mainly for scaffolds printed with the lowest PLT. Besides designed pores, the scaffolds also presented micropores derived from the incomplete sinterisation of PHB particles. This morphology can be advantageous for bone regeneration. The variation of PLT caused a higher difference between the values of scaffold mechanical properties than the variation of SS. The scaffolds, except the one printed with the highest PLT or SS, showed mechanical properties within the lower range of human trabecular bone. 相似文献
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两种聚噻吩类新型电致发光材料的合成与性能 总被引:2,自引:0,他引:2
报道了以无水FeCl3为催化剂合成异戊基取代和戊氧基取代聚噻吩的实验过程,两种聚合物稀溶液和薄膜的光发射、光吸收性能和用这两种材料作发光层制作的发光二极管的光电性能的初步研究结果.两种聚合物均具有较高的纯度和分子量.两种材料均显示了较好的发光性能,其电致发光颜色均为红橙色.烷氧基取代聚噻吩均聚物电致发光性能在学术界尚属首次发现. 相似文献
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For tissue engineering applications, the distribution and growth of cells on a scaffold are key requirements. The potential of biodegradable poly(l-lactide-co-glycolide) (PLGA) polymer with different microstructures, as scaffolds for nerve tissue engineering was investigated. In this study, an attempt was made to develop porous nanofibrous scaffolds by the electrospinning method. In this process, polymer fibers with diameters in the nanometer range are formed by subjecting a polymer fluid jet to a high electric field. Attempt was also made to develop microbraided and aligned microfiber scaffolds. A polymer film scaffold was made by solvent casting method. C17.2 nerve stem cells were seeded and cultured on all the four different types of scaffolds under static conditions for 3 days. Scanning electron micrographs showed that the nerve stem cells adhered and differentiated on all the scaffolds and supported neurite outgrowth. Interesting observation was seen in the aligned microfiber scaffolds, where the C17.2 nerve stem cells attached and differentiated along the direction of the fibers. The size and shape of the cell-polymer constructs remained intact. The present study suggests that PLGA is a potential scaffold for nerve tissue engineering and predicts the orientation and growth of nerve stem cells on the scaffold. 相似文献
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Lao L Wang Y Zhu Y Zhang Y Gao C 《Journal of materials science. Materials in medicine》2011,22(8):1873-1884
Poly(lactide-co-glycolide) (PLGA) nanofibrous composite scaffolds having nano-hydroxyapatite particles (HAp) in the fibers
were prepared by electrospinning of PLGA and HAp with an average diameter of 266.6 ± 7.3 nm. Microscopy and spectroscopy characterizations
confirmed integration of the crystalline HAp in the scaffolds. Agglomerates gradually appeared and increased on the fiber
surface along with increase of the HAp concentration. In vitro mineralization in a 5 × simulated body fluid (SBF) revealed
that the PLGA/HAp nanofibrous scaffolds had a stronger biomineralization ability than the control PLGA scaffolds. Biological
performance of the nanofibrous scaffolds of the control PLGA and PLGA with 5 wt% HAp (PLGA/5HAp) was assessed by in vitro
culture of neonatal mouse calvaria-derived MC3T3-E1 osteoblasts. Both types of the scaffolds could support cell proliferation
and showed sharp increase of viability until 7 days, but the cells cultured on the PLGA/5HAp nanofibers showed a more spreading
morphology. Despite the similar level of the cell viability and cell number at each time interval, the alkaline phosphatase
secretion was significantly enhanced on the PLGA/5HAp scaffolds, indicating the higher bioactivity of the as-prepared nano-HAp
and the success of the present method for preparing biomimetic scaffold for bone regeneration. 相似文献
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采用羧基封端乳酸预聚物与聚乙二醇熔融缩聚合成了聚乳酸-聚乙二醇共聚物,并用GPC、FTIR、1H-NMR等方法表征了预聚物与共聚物,结果表明,预聚物的羧基封端率高于95%,预聚物的相对分子质量可由投料比(物质的量比)控制.热分析结果表明,共聚物中聚乳酸链段呈无规分布,而聚乙二醇链段能够形成结晶微区.力学性能测试结果表明,共聚物的断裂伸长率达371%,有望在聚乳酸韧性改性方面得到应用. 相似文献
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E. Nejati V. Firouzdor M.B. Eslaminejad F. Bagheri 《Materials science & engineering. C, Materials for biological applications》2009,29(3):942-949
In this paper, a new nano-hydroxyapatite / poly (l-lactide acid) (nHAP/PLLA) composite scaffold comprising needle-like nHAP particles was prepared. In the first step, the identification and morphology of chemically synthesized HAP particles were determined by XRD, EDX, FTIR and SEM analyses. The needle-like nHAP particles with an average size of approximately 30–60 nm in width and 100–400 nm in length were found similar to needle-like bone nano apatites in terms of chemical composition and morphology. In the second step, nHAP and micro-sized HAP (mHAP) particles were used to fabricate HAP filled PLLA (HAP/PLLA) composites scaffolds using solid–liquid phase separation method. The porosity of scaffolds was up to 85%, and their average macropore diameter was in the range of 64–175 µm. FTIR and XRD analyses showed the presence of molecular interactions and chemical linkages between HAP particles and PLLA matrix. The compressive strength of nanocomposite scaffolds could high up to 8.46 MPa while those of pure PLLA and microcomposite scaffolds were 1.79 and 4.61 MPa, respectively. The cell affinity and cytocompatibility of the nanocomposite scaffold were found to be higher than those of pure PLLA and microcomposite scaffolds. Based on the results, the newly developed nHAP/PLLA composite scaffold is comparable with cancellous bone in terms of microstructure and mechanical strength, so it may be a suitable alternative for bone tissue engineering applications. 相似文献
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Xiqin Lü Wanyin Zhai Yanling Zhou Yue Zhou Hongfeng Zhang Jiang Chang 《Journal of materials science. Materials in medicine》2010,21(2):473-480
Decellularized heart valve scaffolds possess many desirable properties in valvular tissue engineering. However, their current
applications were limited by short durability, easily structural dysfunction and immunological competence. Although crosslinking
with chemical reagents, such as glutaraldehyde (GA), will enhance the mechanical properties, the low long-term stability and
cytotoxicity of the scaffolds remains potential problem. Nordihydroguaiaretic acid (NDGA) is a bioactive natural product which
is able to crosslink collagen and was proven to be effective in preparation of scaffold for tendon tissue engineering. In
this paper, NDGA crosslinked decellularized heart valve scaffolds demonstrated higher tensile strength, enzymatic hydrolysis
resistance and store stability than the non-crosslinked ones. Its mechanical properties and cytocompability were superior
to that of GA-crosslinked heart valve matrix. Below the concentration of 10 μg/ml, NDGA has no visible cytotoxic effect on
both endothelial cells (EC) and valvular interstitial cells (VIC) and its cytotoxicity is much less than that of GA. The LC50
(50% lethal concentration) of NDGA on ECs and VICs are 32.6 μg/ml and 47.5 μg/ml, respectively, while those of GA are almost
30 times higher than NDGA (P < 0.05). ECs can attach to and maintain normal morphology on the surface of NDGA-crosslinked valvular scaffolds but not GA-crosslinked
ones. This study demonstrated that NDGA-crosslinking of decellularized valvular matrix is a promising approach for preparation
of heart valve tissue engineering scaffolds. 相似文献
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采用溶液聚合法合成了生物降解材料聚丙烯酸-聚乳酸接枝共聚物(PAA-g-PLLA),通过红外、核磁和凝胶渗透色谱对其结构进行了表征,测定了涂膜的附着力、黏度和硬度等基本性能。正交实验结果表明最佳的合成工艺条件为:硬软单体的质量比为55∶35,过氧化苯甲酰(BPO)的用量为3%,反应温度为85℃,甲基丙烯酸羟乙酯-聚乳酸大单体(HEMA-PLLA)与软硬单体的质量比为1∶2,单体与溶剂的质量比为2∶2。对比聚丙烯酸涂膜和PAA-g-PLLA涂膜的接触角,以及PLLA降解性能看出,PAA-g-PLLA涂膜具有降低表面能和自抛光的双重特性。 相似文献
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以0.35%(质量分数)的过氧化二异丙苯(DCP)为引发剂和2%(质量分数)的马来酸酐(MAH)为增容剂,通过原位反应挤出的方法制备了聚乳酸(PLLA)/聚醚酯嵌段共聚物(TPEE)合金。利用TG、差示扫描量热(DSC)、SEM等研究了其热性能和相形态,并测试了合金的力学性能和熔体流动速率。结果表明,在引发剂DCP的存在下,MAH的添加使得反应挤出制备的合金中PLLA与TPEE之间产生部分共价键连接而增加了相容性。合金的热稳定性、韧性随TPEE含量的增加而升高,但模量和强度下降。另外,不同TPEE含量的合金的熔体流动速率均高于纯PLLA和TPEE,表明在原位反应挤出过程中PLLA与TPEE均发生了一定程度的降解反应。同时,对合金的流变性能也进行了研究。 相似文献
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分别采用反应性和非反应性熔融共混方法结合粒子沥滤技术以及碱处理技术构建不同质量比的聚(3-羟基丁酸酯-3-羟基戊酸酯)(PHBV)/聚碳酸亚丙酯(PPC)复合支架,通过表征支架的表面形态、孔隙率大小和体外降解性能,发现反应性共混法可显著改善支架的相容性和界面粘接。非反应性熔融共混法构建的支架孔隙率高于反应性共混法构建的复合支架。随着PPC含量的升高,复合支架的孔隙率升高。当PHBV/PPC质量比达50/50时,支架在PBS缓冲液中降解最快,反应性共混法构建的支架亲水性高于非反应性共混法,碱处理技术可显著改善复合支架的亲水性。这对功能重建的体内研究和临床实践具有潜在的理论价值和应用前景。 相似文献
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J.F.A. Valente T.A.M. Valente P. Alves P. Ferreira A. Silva I.J. Correia 《Materials science & engineering. C, Materials for biological applications》2012,32(8):2596-2603
The design and production of scaffolds for bone tissue regeneration is yet unable to completely reproduce the native bone properties. In the present study new alginate microparticle and microfiber aggregated scaffolds were produced to be applied in this area of regenerative medicine.The scaffolds' mechanical properties were characterized by thermo mechanical assays. Their morphological characteristics were evaluated by isothermal nitrogen adsorption and scanning electron microscopy. The density of both types of scaffolds was determined by helium pycnometry and mercury intrusion porosimetry. Furthermore, scaffolds' cytotoxic profiles were evaluated in vitro by seeding human osteoblast cells in their presence.The results obtained showed that scaffolds have good mechanical and morphological properties compatible with their application as bone substitutes. Moreover, scaffold's biocompatibility was confirmed by the observation of cell adhesion and proliferation after 5 days of being seeded in their presence and by non-radioactive assays. 相似文献
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文中探究不同相对分子质量聚乙二醇(PEG)对聚乳酸(PLA)增塑改性的影响。采用转矩流变仪、万能试验机、差示扫描量热分析、动态力学、热重分析、旋转流变仪等测试表征方法对共混材料的增塑效果、力学性能、热行为、流变行为进行分析。实验结果表明,PEG可有效增塑PLA,PEG相对分子质量越低增塑效果越好,可以使PLA的塑化时间从250 s降低到128 s;加入PEG后,共混物的拉伸强度下降,断裂伸长率提高,PEG相对分子质量越低,拉伸强度下降越明显;PEG的加入使PLA的T_g和T_(cc)降低20℃左右,而T_m有所提高,其中低相对分子质量PEG可以更好地促进PLA结晶,但是随着PEG的加入共混体系的热分解温度降低,相对分子质量越低,热分解温度降低越明显;流变实验表明共混体系的复数黏度(η*)、储能模量(G')及损耗模量(G')的变化随PEG相对分子质量的减小下降越明显。 相似文献
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G. Ciardelli B. Saad T. Hirt O. Keiser P. Neuenschwander U. W. Suter G. K. Uhlschmid 《Journal of materials science. Materials in medicine》1995,6(12):725-730
The biocompatibility and the degradation mechanisms of block co-polyurethanes containing crystallizable telechelic poly [(R)-3-hydroxybutyric acid] (PHB) segments have found recently growing interest for the possible biomedical applications of these new materials. The random hydrolytic cleavage of the amorphous part of these polymers might result, in vivo, in the production of small crystalline particles of low molecular weight PHB that could then undergo phagocytosis and biodegradation inside phagosomes. To test this possibility, a fluorescent-labelled PHB segment was synthesized, precipitated in the form of crystalline particles, and used for an in vitro investigation of its interaction with macrophage cell line. Light and fluorescence microscopy performed in the present study clearly show that the fluorescent particles are well internalized in phagosomes already after 1 h of incubation. The number of phagocytized particles decreases notably after 8 days of incubation.A quantitative determination of the time dependence of the phagocytosis was obtained through laser cytometry and fluorescence-activated cell sorting (FACS). Fluorescence spectroscopy and high-performance liquid chromatography (HPLC) analysis of extracts of cell supernatants revealed the presence of supposed degradation products of PHB after 8 days of incubation, suggesting that macrophages could degrade low molecular weight PHB. 相似文献
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目的综述近年来国内外聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PHBV)的改性研究进展,为进一步开发PHBV在包装领域的应用提供科学的理论基础。方法以PHBV薄膜材料为主,根据PHBV的优缺点,从物理改性和化学改性2个方面进行阐述。结果 PHBV是一种拥有生物可降解性的热塑性树脂,具有广阔的应用前景,但PHBV的脆性大、韧性差,必须对其进行改性,且物理和化学改性均有优缺点。结论大量研究表明,PHBV经过改性后性能有所改善,但由于其相容性差导致复合材料性能的提升幅度有限,因此,有待开发和完善PHBV的生物降解性,且工艺简单、成本又低的改性技术。 相似文献