可吸收HA／PDLLA内固定材料组织相容性观察

可吸收骨折内材料要求具有很好的组织相容性,本文将自行研制的可吸收羟基磷灰石／聚ＤＬ乳酸（ＨＡ／ＰＤＬＬＡ）内固定材料植入兔肌肉和骨组织中,于３,６,２１,２４,３６,５２周取材,作ｘ线摄片和组织学观察。结果;骨折在６周内正常愈合,５２周内组织反应较轻,无大量炎性细胞集聚。结论：ＨＡ／ＰＤＬＬＡ复合材料具有很好的组织相容性。     

RPS／LLDPE反应性共混研究

用ＨＡＡＫＥ、ＩＲ、ＤＳＣ研究了侧基含有过氧键的活性聚苯乙烯（ＲＰＳ）与线性低密度聚乙烯（ＬＬＤＰＥ）之间的反应,用ＳＥＭ观察了共混物的断面形态,结果表明：共混反应中生成了ＰＳ－ｇ－ＬＬＤＰＥ,对ＬＬＤＰＥ／ＰＳ共混物具有增容作用,提高了共混物的机械性能。     

引导组织再生PDLLA／β—TCP膜的降解性能研究

聚ＤＬ－乳酸、β－磷酸钙（ＰＤＬＬＡ／β－ＴＣＰ）膜进行了体内外降解性能研究。体外将膜置于温度为３７℃、ｐＨ＝７．４的缓冲溶液中,分２、４、８、１２、１６周取样,进行分子量测试及ＳＥＭ观察。体内选取小鼠１５只,将膜同期植入小鼠皮下,分别于２、４、８、１２、１６周处死小鼠,切取标本,常规制片,光镜下观察。本文认为：ＰＤＬＬＡ／β－ＴＣＰ具有良好的生物相容性、可性及骨结合能力,膜材具有一定的原理度和韧     

PA6/EHDPET纺丝样品的扫描电镜制样

用甲酸和甲醇钠对ＰＡ６／ＥＨＤＰＥＴ熔融共混纺丝样品（熔块和纤维）进行刻蚀处理,并对熔块和纤维用多种方法试样,扫描电镜对共混纺丝样品形态结构的观察结果表明：样品经刻蚀处理并选择合适的方法制样,即可清晰地观察到ＰＡ６／ＥＨＤＰＥＴ共混物样品的海－岛结构。     

阻隔性HDPE／PA—6共混合金的设计与制备

通过对３种相对粘度不同的ＰＡ－６进行混溶性研究，筛选出一种适合于作阻镉改性剂的ＰＡ－６。同时测定了ＨＤＰＥ、ＰＡ－６的流变性能及对共混物进行了ＰＣＭ分析，摸索出制备阻隔性ＨＤＰＥ／ＰＡ－６共混合金的工艺条件，如加工温度，剪切速率和混合时间等。     

HDPE／HDPE—g—MAH／CaCO3材料流变性能研究

目的 研究ＨＤＰＥ／ＨＤＰＥ－ｇ－ＭＡＨ／ＣａＣＯ３共混物的流变性能。方法 借助毛细管流变仪,考查了ＣａＣＯ３含量,ＨＤＰＥ－ｇ－ＭＡＨ含量对共混材料流变 性能的影响。结果 ＣａＣＯ３和ＨＤＰＥ－ｇ０ＭＡＨ的加入使体系的粘度上升,体系的非牛顿性增强。结论 研究结果对生产工艺和模具设计具有指导意义。     

聚烯烃相容剂改性尼龙6的研究

用聚烯烃（ＰＯ） 与马来酸酐接枝物（ＰＯ－ｇ－ＭＡＨ） 作为相容剂, 讨论了ＰＯ－ｇ－ＭＡＨ对ＰＯ／ＰＡ－６ 及ＰＯ／ＰＯ－ｇ－ＭＡＨ／ＰＡ－６ 体系的物理机械性能的影响。结果表明相容剂对ＰＯ／ＰＡ－６ 共混体系具有较好的增容作用, 提高冲击强度, 降低了吸水性, 促进分散相细化, 提高了界面的键合力, 增加了ＰＡ－６ 基体的粘度, 改善了ＰＡ－６ 的加工性     

尼龙6／聚丙烯共混材料性能的研究

采用ＰＰ－ｇＭＡＨ为相容剂，研究了各组成份对ＰＡ６／ＰＰ共混材料的拉伸性能和冲击性能的影响。探讨了三元乙丙橡胶（ＥＰＤＭ）的增韧作用及共混物变性能的变化。     

用MAH改性PE和EPDM增韧PA-66及增韧机理分析

用马来酸酐（ＭＡＨ）熔融接枝聚乙烯（ＬＤＰＥ）和三元乙丙胶（ＥＰＤＭ）改善了与基体ＰＡ－６６的相溶性，继而大幅度地提高了ＰＡ－６６／（ＰＥ）／ＥＰＤＭ）－ｇ－ＭＡＨ的冲击强度。当共混物中ＥＰＤＭ－ｇ－ＭＡＨ为９％、ＰＥ－ｇ－ＭＡＨ为３０％时，共混材料的冲击强度是ＰＡ－６６的３．３５倍，成本降低约１５％。同时对增韧机理进行了分析     

用MAH改性PE和EPDM增韧PA—66及增韧机理分析

用马来酸酐ＭＡＨ熔接枝聚乙烯（ＬＤＰＥ）和三元乙丙胶（ＥＰＤＭ）改善了与基体ＰＡ－６６的相溶性、继而大幅度地提高了ＰＡ－６６／（ＰＥ／ＥＰＤＭ）－ｇ－ＭＡＨ的冲击强度。当共混物中ＥＰＤＭ－ｇ－ＭＡＨ为９％、ＰＥ－ｇ－ＭＡＨ为３０％时，共混材料的冲击强度为ＰＡ－６６的３．３５倍，成本降低约１５％。同时对增韧机理进行了分析。     

BIODEGRADATION AND MECHANICAL PROPERTIES OF HYDROXYAPATITE/POLY-DL-LACTIDE COMPOSITES FOR FRACTURE FIXATION

The biodegradation and mechanical properties of self-designed hydroxyapatite/poly-DL-lactide (HA/PDLLA) compositites -were investigated in vitro and invio. In vitro, the specimens of HA/PDLLA and unfilled PDLLA -with similar molecular weights were immersed in phosphate-buffered saline. Ageing of the various devices were monitored by measuring molecular weight,water absorption, weight loss, PH, mechanical strengths and mi-crostructural changes. The follow-up times were 2, 4 , 6 , 8, 10 and 12 weeks. In vivo, a transverse transcondylar osteotomy of the distal femur was fixed with a HA/PDLLA rod (diameter, 4. 5mm;length, 30-40mm). The follow-up times were 3. 6 and 12 weeks. Roentgenographic, histologic, and biomechanical studies were carried out. The results show that the HA/PDLLA composities have higher mechanical strength and slower degradation than that of the unfilled PDLLA and that of all osteotomies unite within six weeks without delay. Consequently, the HA/PDLLA composites possess sufficient mechani     

Biodegradation of Absorbable Hydroxyapatite／Poly—DL—lactide COmposites in Different Environment

To develop a new generation of absorbable fracture fixation devices with enhanced biocompatibility,the biodegradation mechanism and its influence on the cellular response at the tissue/implant interfoce of hydroxyapatite/poly-DL-lactide(HA/PDLLA) composites were investigated in vitro and in vivo.HA/PDLLA rods were immersed in phosphate-buffered saline,or implanted in muscle and bony tissue for 52 weeks.Scanning electron microscopic and histological studies were done.The degradation rate was the slowest in vitro,slower in muscle tissue and fast in bone.In vitro,the composites degraded heterogeneously and a hollow structure was formed.In bone,the limited clearing capacity leads to the accumulation of oligomeric debris,which contribute totally to the autocatalytic effect.So,the fastest degradation and intense tissue response were seen.In muscle tissue,oligomeric debris migratred into vicinal fibers over a long distance from the original implant cavity and the tissue reactions were,however,quite moderate.For the same size organic/inorganic composite,the environment where it was placed is the major factor in determining its biodegradation process and cellular reaction.In living tissue,tactors such as cells,enzymes and mechanical stress have an obvious influentce on the biodegradation and biological process at the tissue/implant interface,The biocompatibility of the HA/PDLLA composistes is enhanced with the incorporating of the resorbable HA microparticles.     

PDLLA/HA/FK506复合神经导管的制备及体外降解性能

以聚乳酸（PDLLA）为基材、纳米羟基磷灰石（HA）为添加剂、加入免疫抑制剂FK506，用溶剂挥发法制备PDLLA／HA/FK506复合神经导管。通过观察复合导管在磷酸缓冲溶液中降解时pH值变化、质量损耗及材料微观形貌，研究了该复合导管的体外降解性能。结果表明：加入适量纳米羟基磷灰石可以改善聚乳酸降解的酸性问题并提高其力学强度。免疫抑制剂FK506的加入对导管材料的降解性能有一定的影响。PDLLA/HA／FK506复合神经导管具有良好的降解性能。     

几种聚乳酸／生物活性陶瓷复合材料细胞相容性的比较

采用溶解共混法制备含30%硅灰石的聚乳酸/硅灰石新型生物医用复合物膜.将大鼠成骨细胞ROS 17/28系种植在复合物表面使其存活,考察生长情况和复合物的生物活性,并与目前研究应用较多的聚乳酸/羟基磷灰石、聚乳酸/磷酸三钙及聚乳酸/珍珠层粉复合物进行比较.荧光染色实验及MTT测试表明,4种复合物膜表面细胞均可以正常的生长和增殖,且呈现出聚乳酸/珍珠层粉>聚乳酸/硅灰石>聚乳酸/羟基磷灰石>聚乳酸/磷酸三钙的结果,说明聚乳酸/硅灰石复合物材料具有较好的细胞相容性,适于应用在骨修复及骨组织工程领域.     

Evaluation of a novel bioabsorbable PRGD/PDLLA/<Emphasis Type="Italic">β</Emphasis>-TCP/NGF composites in repair of peripheral nerves

Peripheral nerve regeneration using a novel nerve conduit (PRGD/PDLLA/β TCP/NGF) was evaluated, which was made of RGD peptide modified poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PRGD), poly(d,l-lactic acid) (PDLLA) and β-tricalcium phosphate (β-TCP). And the effectiveness was compared with that of PRGD/PDLLA/β-TCP, PDLLA and autograft in terms of nerve regeneration across a gap. Both of biodegradablity and cell-biocompatibility of the novel nerve conduit were evaluated in vitro. The results show that PRGD/PDLLA/β-TCP/NGF composite materials have better biodegradation properties and cell affinity than PDLLA, and could promote the RSC96 Schwann cells adhesion, proliferation and growth on the surface of materials. PRGD/PDLLA/β-TCP/NGF composite conduit was significantly superior to that of the PDLLA conduit in histological and axon morphologic index. PRGD/PDLLA/β-TCP/NGF conduit is more beneficial to nerve regeneration than PDLLA conduit. The biodegradable PDLLA/PRGD/β-TCP/NGF conduit has a good biocompatibility with rats tissue and it could effectively promote the nerve regeneration after bridging sciatic nerve defect of rats, the effect is as good as that of the autograft nerve, significantly superior to the PRGD/PDLLA/β-TCP conduit and PDLLA conduit. PDLLA/PRGD/β-TCP/NGF composite conduit is a potential ideal conduit. Funded by 973 State Key Fundamental Research and Development (No. G2005CB623905)     

In vitro biocompatibility assessment of a novel PRGD/PDLLA/NGF composite material

The objective of this study was to evaluate the degradability and biocompatibility of a novel composite materials which was grafted with RGD and immobilized with NGF(PRGD/PDLLA/NGF). The releasing of NGF, the biodegradability and cell-biocompatibility of PRGD/PDLLA/NGF membrane were evaluated in vitro. The experimental results showed that the NGF release process was prolonged over 30 days. Furthermore, the PRGD/PDLLA/NGF showed a better hydrophilicity, better biodegradation properties and cells affinity than PDLLA, which means a good support to adhesion and proliferate of Schwann cells. Therefore, the novel composite material holds considerable promise as scaffolds in nerve tissue engineering.     

The Study of Nerve Conduit with Biocompatibility and Electrical Stimulation Effect

Conductive polymers show great promise because of their electrical property based on bioelectricity in vivo. In order to search electro-activity materials which insure abduction of tissue, we synthesized conductive nerve conduits with poly-dl-lactic-acid(PDLLA) and tetra-aniline(TA). Preparation technology of TA was optimized, and the properties of the conduit were studied. RSC96 cell were used to investigate the toxicity and electrical stimulation effect. SD rats were used to assess biocompatibility in vivo. The results showed that the reaction ratio of 1:1, the reaction time of 2 h and the HCl concentration of 2 mol/L were the optimum conditions for synthesis of TA. The influence of TA content on the mechanical properties, hydrophilicity, conductivity and microstructure of the nerve conduit was evaluated. Cell and histocompatibility study showed PDLLA/TA possessed good biocompatibility. These results showed it had application values in tissue projects.     

In vitro Degradation of Butanediamine-Grafted Poly（DL-Lactic acids）

The degradation of butanediamine-grafted poly（DL-lactic acid） polymers （BDPLAs） in vitro together with PDLLA and maleic anhydride-grafted poly（DL-lactic acid） polymers （MPLAs） was investigated by observation of the changes of the pH value of incubation media, and weight loss ratio during degradation duration of 12 weeks. The results reveal that the acidity of PDLLA degradation products was weakened or neutralized by grafting butanediamine onto PDLLA. A uniform degradation of BDPLAs was observed in comparison with an acidity-induced auto-accelerating degradation featured by PDLLA and MPLAs. The biodegradation behaviors of BDPLAs can be adjusted by controlling the content of BDA. BDPLAs might be a new derivative of PDLLA-based biodegradable materials for medical applications without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as that of PDLLA.     

The enhancement of osteogenesis by scaffold based on mineralized recombinant human-like collagen loading with rhBMP-2

A biomimetic scaffold based on mineralized recombinant collagen, nano-hydroxyapatite/recombinant human-like collagen/poly(lactic acid) (nHA/RHLC/PLA), was prepared with recombinant human bone morphogenic protein-2 (rhBMP-2) for improving the osteoinductive property of the scaffold. The nHA/RHLC/PLA scaffolds loaded with 10 μg rhBMP-2 and the unloaded scaffolds were implanted subcutaneously in the rat model. The osteogenetic capacity of these composites was evaluated by CT scan, ALP activity test and histological observation at 4 and 8 weeks after implantation. The experimental results indicated that the osteogenic capability of the scaffolds loaded with rhBMP-2 was superior to the unloaded scaffold. It was concluded that rhBMP-2 can enhance the osteoinductive property of the nHA/RHLC/PLA scaffold and the nHA/RHLC/PLA scaffold loaded with rhBMP-2 have the good potential of being used in bone tissue engineering.     

Preparation and Evaluation of an Injectable Chitosan-Hyaluronic Acid hydrogel for Peripheral Nerve Regeneration

The aim of this study was to obtain the fillers in the lumen of hollow nerve conduits(NCs) to improve the microenvironment of nerve regeneration. A p H-induced injectable chitosan(CS)-hyaluronic acid(HA) hydrogel for nerve growth factor(NGF) sustained release was developed. Its properties were characterized by gelation time, FT-IR, SEM, in vitro swelling and degradation. Furthermore, the in vitro NGF release profiles and cell biocompatibility were also investigated. The experimental results show that the CS-HA aqueous solution can undergo a rapid gelation 3 minutes after its environmental p H is changed to 7.4. The CSHA hydrogel has interconnected channels with a controllable pore diameter and with a porosity of about 80%. It has a favorable swelling behavior and can be degraded by about 70% within 8 weeks in vitro and is suitable for NGF release. The CS-HA/NGF hydrogel exhibits a lower cytotoxicity and is in favor of the adhesion and proliferation of the BMMSCs cells. It is indicated that the CS-HA/NGF will be a promising candidate for neural tissue engineering.