基于再生纤维素皮肤修复材料的制备及其性能

背景：再生纤维素膜具有很好的吸湿性和机械强度且生物降解性优良,但其韧性较差,有研究结果表明再生纤维素膜干膜的伸长率不足15%。 目的：制备复合型2,3-二醛纤维素/胶原蛋白膜,并检测其机械性能、溶胀性能、透湿性和保水率等性能。 方法：采用高碘酸钠氧化改性制备2,3-二醛纤维素/胶原蛋白膜,采用红外光谱和扫描电子显微镜观察其形态结构,并检测其机械性能、溶胀性能、透湿性和保水率,同时以再生纤维素膜、2,3-二醛纤维素膜为对照;将对数生长期小鼠胚胎成纤维细胞株接种于2,3-二醛纤维素/胶原蛋白膜上培养,1,3,5 d后采用MTT法检测细胞增殖。 结果与结论：红外光谱证实胶原蛋白成功固化到2,3-二醛纤维素膜表面;扫描电镜显示,2,3-二醛纤维素/胶原蛋白膜具有疏松的多孔结构,胶原蛋白的固定使材料表面部分具有多孔网络结构,孔隙率为93.4%。2,3-二醛纤维素/胶原蛋白膜的机械性能、溶胀率、透湿性均强于2,3-二醛纤维素膜、再生纤维素膜(P < 0.05),3组之间保水率差别不大。小鼠胚胎成纤维细胞在再生纤维素/胶原蛋白膜表面黏附紧密,形态伸展并呈现出不断增殖的趋势。表明2,3-二醛纤维素/胶原蛋白膜具有良好的机械性能、溶胀性能、透湿性及保水率,以及细胞相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

稳定脊柱前柱的一种新型复合装置

广泛应用的脊柱前柱固定方法均有不足之处，特别是对神经弓有缺陷的病人。实验研究（１８只犬）和临床实验（２４个病人）表明，ＢＯＰ－Ｂ是一种很好的塑性材料，用以固定脊柱前柱可缩短手术时间，减少手术创伤。该材料有良好的生物结合性能，类似于骨组织。该材料不足之处是，在骨形成的头一个月，矫正畸形可有部分丢失。１９８８年以来，以多孔镍钛植入物治疗２９位病人，并取得改善。该材料的生物力学特性类似于骨组织，即使在没有固定的情况下，畸形矫正再丢失也极少。１９９３年，６位病人手术时用了一种新型复合植入物。该植入物由多孔镍钛和ＢＯＰ－Ｂ组成兼具两者的特性。在骨形成阶段，多孔镍钛对ＢＯＰ－Ｂ有支持作用。ＢＯＰ－Ｂ既能引导骨长入，又能起复合固定作用。以这种新型复合植入物固定不仅可允许病人术后立即活动锻炼，而且允许进行对照检查，包括作ＭＲＩ检查也不会出现伪影。该植入物已成功地用于颈段和胸腰段脊柱的固定。     

生物降解性防术后粘连膜的实验研究

本文首次采用新型医用天然高分子材料壳聚糖作膜材料，制备了可降解吸收防术后粘连膜，并通过动物实验研究其生物降解性和生物相容性．初步研究结果表明，壳聚糖具有很好的成膜性。壳聚糖膜在小鼠体内可以缓慢降解，并具有较好的生物相容性，是一种很有发展前景的天然防术后粘连膜材料。     

敷料用透湿性聚氨酯膜的性能及其影响因素

我们用聚乙二醇(PEG)代替普通聚醚(PPG)合成了亲水性的聚氨酯(PU)预聚体,然后将预聚体溶液流延成膜制成双层敷料的外层透湿膜.研究了PEG分子量、交联剂用量、制膜溶剂及预聚体溶液中水含量对膜透湿性的影响.结果表明所制的膜是一种多孔结构的透湿膜;适宜的成膜条件为PEG的分子量(Mn)为2000～4000,交联剂用量为5.0wt%,成膜溶剂为丙酮与N,N-二甲基-甲酰胺的混合溶液,成膜温度为50℃～80℃;所制膜的透湿率在35℃下为49～60g/m2h,能够满足敷料对透湿率的要求;并对它的透湿过程机理进行了探讨.     

生物降解性防术后粘加膜的实验研究

本文首先采用新型医用天然高分子材料壳聚糖作膜材料，制备了可降解吸收的防术后粘连膜，并通过动物实验研究其生物降解性和生物相容性。初步研究结果表明，壳聚糖具有很好的成膜性。壳莫大 半导体环境可以缓慢降解，并具有较好的生物相容性，是一种很有发展前景的天然防术后宫膜材料。     

多孔壳聚糖膜材料的制备及性能研究

为获得一种多孔的壳聚糖膜材料 ,本文探讨了致孔剂聚乙二醇不同分子量和不同用量对膜内孔结构、含水率和保液性的影响 ,通过实验选择出致孔剂聚乙二醇的分子量为 2 0 0 0 ,用量为 0 .8% ,通过扫描电镜观察壳聚糖多孔高分子材料理想内部孔洞尺寸为 1.84μm,孔洞体积分数为 196.5% ,含水率为 66.2 3% ,保液性 2 .0 9g/ g     

生物材料与犬体内动态血液接触对血生化,血象及生命体征影响

参照有关标准方法，将醋酸纤维素（ＣＡ）、聚醚砜（ＰＥＳ）及聚氨酯１１型（ＰＵ－Ⅱ）三种生物材料加工深层于聚氯乙烯（ＰＶＣ）管壁内，在蠕动泵作用下进行犬体内血液循环接触，按接触的不同时间观察血生化、血象及生命体征的变化。结果表明：ＣＡ材料接触后５－３０ｍｉｎ白细胞（ＷＢＣ）明显降低，随后有上升趋势，血清中白蛋白（Ａｌｂ）、总蛋白（ＴＰ）、血糖（Ｇｌｕ）及总胆固醇可见轻微下降，硷性磷酸酶（ＡＩＰ）增加，心率、血压及呼吸在接触后的某些时间范围内与接触前比稍有变化，而ＰＥＳ和ＰＵ－Ⅱ两种材料接触前后变化不明显，两种材料之间及不同时间之间比无明显差异。     

人工细胞愈合膜研制成功

人工细胞愈合膜研制成功由杭康药业公司运用高新技术研制成功的人工细胞愈合膜通过了浙江省级鉴定。人工细胞愈合膜是由人工细胞组成的活体医用材料，其中人工细胞的营养成分构成与人体细胞极为相似。这种愈合膜覆盖于皮肤创口上后，材料中的细胞即可与创面细胞吸附或融合...     

生物人工肝的新型免疫屏障膜

由于不相容的蛋白交换使生物人工肝装置中的异种性或遗传改性肝细胞产生某些副作用，是肝衰治疗中的主要问题，从而限制了生物人工肝对于肝功能不全的治疗应用。因此有待研制一种蛋白不能透过的屏障膜。一种新型的免疫膜屏障可防止生物反应器所合成的动物蛋白（包括白蛋白）与来自患者血液的人体蛋白发生混合。此种膜屏障还可有效促进人体蛋白发生混合。此种膜屏障还可有效促进人体血液与哺乳动物肝细胞之间的白蛋白结合毒素的交换即通过一种选择性载体介导的膜传递。膜由酰胺聚合物组成，含亲水与疏水微区，配体素样蛋白固定在内部多孔膜结…     

合成聚肽膜渗透抗癌药物的研究

本文制备了聚谷氨酸苄酯膜，并进行皂化，得到了谷氨酸苄酯－谷氨酸共聚物膜．研究了不同聚合物膜对两种抗癌药物５－氟脲嘧啶（５Ｆｕ）及２－羟乙基－氧甲基－５－氟脲嘧啶（２－ＨＥＯＭ－５－ＦＵ）的渗透性能。结果表明Ｐ１（ＢＬＧ－ＬＧＡ）膜渗透５－Ｆｕ和２－ＨＥＯＭ－５－Ｆｕ的渗透系数分别是ＰＢＬＧ膜的４和１６倍，且Ｐ２（ＢＬＧ－ＬＧＡ）膜的渗透系数分别是ＰＢＬＧ膜的１３和２６倍．     

In vitro effect on cancer cells: synthesis and preparation of polyurethane membranes for controlled delivery of curcumin

Urethane polymers (PU) have been prepared from low-molecular weight polylactic acid (PLA) and hexamethylene diisocyanate (HMDI) using polydimethylsiloxane (PDMS) as a chain extender. These formed the supporting polymeric matrix of curcumin-containing PU membranes which were prepared using a solvent evaporation technique. FTIR and XRD data indicated the molecular-level dispersion and random distribution of curcumin in the polymer matrix, and data were consistent with observations from tensile-strength measurements and from AFM imaging. Determination of water vapor permeability and moisture uptake measurements have indicated that the PU membrane were appropriate for use on human skin. Skin permeation studies of curcumin were consistent with zero order (R2 = 0.9874) and with Korsmeyer-Peppas (R2 = 0.9978) kinetics-analytical data pointed to permeation by a combination of diffusion and erosion processes, with the latter dominating. The biocompatibility of these PU membranes was indicated by in vitro cytotoxicity studies using 3T3-L1-murine fibroblast cell. The in vitro therapeutic potential of the patches was demonstrated against A549 human lung cancer cells.     

Membrane distillation of human plasma ultrafiltrate and its theoretical applications to haemodialysis techniques

Membrane Distillation (MD) is a technique that allows the extraction of water from aqueous solutions. The basic principle is that vapour, but not liquid water, can pass through hydrophobic micro-porous membranes, along a temperature gradient, with consequent separation of water from solutes. In this study we evaluated the possibility to utilise MD to extract water from Plasma Ultrafiltrate (PU) of patients with Chronic Renal Failure (CRF). The experiments were carried out in vitro by a hydro-phobic polypropylene hollow-fibre distillation module; PU was obtained by a CRF patient utilising a high permeability polisulphone membrane. The results show that water can be extracted by MD from PU of CRF subjects at a constant rate and that none of the substances analysed in PU was able to pass through the polypropilene membrane. In the future MD could integrate extra-corporeal blood purification techniques allowing the re-utilisation of plasmatic water thus ameliorating the treatment of uraemia.     

Porous and single-skinned polyethersulfone membranes support the growth of HepG2 cells: a potential biomaterial for bioartificial liver systems

In this study, we evaluated a porous and single-layer skin polyethersulfone (PES) membrane as a material for use in hybrid bioartificial liver support systems. The PES membrane has been characterized as a single-layer skin structure, with a rough porous surface. Specifically, we studied the ability of the human hepatoblastoma cell lines (HepG2) to adhere, grow, and spread on the PES membrane. Furthermore, we examined albumin secretion, low-density lipoprotein uptake, and CYP450 activity of HepG2 cells that grew on the membrane. HepG2 cells readily adhered onto the outer surfaces of PES membranes. Over time, HepG2 cells proliferated actively, and confluent monolayer of cells covered the available surface area of the membrane, eventually forming cell clusters and three-dimensional aggregates. Furthermore, HepG2 cells grown on PES membranes maintained highly specific functions, including uptake capability, biosynthesis and biotransformation. These results indicate that PES membranes are potential substrates for the growth of human liver cells and may be useful in the construction of hollow fiber bioreactors. Porous and single-layer skin PES membranes and HepG2 cells may be potential biomaterials for the development of biohybrid liver devices.     

Transport of water vapour and gases in modified cellulose acetate matrices. Influence of the nature of the penetrant on diffusion and relaxation kinetics

Membranes developed by modification of a cellulose acetate (CA) matrix were studied by means of the flow method CA matrix is modified by poly(4-vinylpyridine) (PVP), or an interpenetrating network (IPN) agent. The obtained diffusion coefficients, permeability coefficients and relaxation kinetic parameters for oxygen, carbon dioxide and water vapour enabled us to consider not only the transport properties of the membranes but also the influence of the relaxation processes on the membrane permeability and stability. The results show that the interactions between water molecules and polar groups on the polymer chains cause the membrane material to swell. This swelling process provokes an increase in the permeation flux of ca. 20–30%. Oxygen causes a consolidation of unstable membranes of the cellulose acetate matrix modified by IPN but not of blends with PVP. The consolidation process reduces the membrane permeability by ca. 38%, while carbon dioxide has no effects on the membrane properties. Membranes based on a modified cellulose acetate matrix have higher permeability than pure CA membranes.     

Asymmetric Composite Membranes from Chitosan and Tricalcium Phosphate Useful for Guided Bone Regeneration

Abstract

To fulfill the properties of barrier membranes useful for guided bone tissue regeneration in the treatment of periodontitis, in this study a simple process combining lyophilization with preheating treatment to produce asymmetric barrier membranes from biodegradable chitosan (CS) and functional β-tricalcium phosphate (TCP) was proposed. By preheating TCP/CS (3:10, w/w) in an acetic acid solution at 40°C, a skin layer that could greatly increase the mechanical properties of the membrane was formed. The asymmetric membrane with a skin layer had a modulus value almost 4-times that of the symmetric porous membrane produced only by lyophilization. This is beneficial for maintaining a secluded space for the bone regeneration, as well as to prevent the invasion of other tissues. The subsequent lyophilization at ?20°C then gave the rest of material an interconnected pore structure with high porosity (83.9–90.6%) and suitable pore size (50–150?μm) which could promote the permeability and adhesiveness to bone cells, as demonstrated by the in vitro cell-culture of hFOB1.19 osteoblasts. Furthermore, the TCP particles added to CS could further increase the rigidity and the cell attachment and proliferation of hFOB1.19. The TCP/CS asymmetric composite membrane thus has the potential to be used as the barrier membrane for guided bone regeneration.     

Porosity effects of natural latex (Hevea brasiliensis) on release of compounds for biomedical applications

Natural rubber latex biomedical (NRLb) obtained from the rubber tree Hevea brasiliensis has shown great potential in biomedicine and biomaterial applications. NRLb has been utilized as a physical barrier against infectious agents and in the controlled release of drugs and extracts. In the present work, NRLb was polymerized in a lyophilizer using different volumes of water to control the resultant membrane porosity and characterized regarding the surface morphology, water vapour permeability (WVP), mechanical properties, haemolytic activity and cytotoxicity. The release of bovine serum albumin protein from the latex membranes was evaluated. Drug release rates increased with porosity and membranes were able to control protein release up to 12 h. In addition, WVP increased with the quantity of pores. The cell viability observed for the porous membrane was higher than that noted for conventional membranes. In summary, the porosity control of natural latex membranes can be used to modulate properties and make them suitable for biomedical applications, such as wound dressings, modulated gas-exchange membranes and controlled drug delivery systems.     

Asymmetrically porous PLGA/Pluronic F127 membrane for effective guided bone regeneration

Porous guided bone regeneration (GBR) membranes with selective permeability, hydrophilicity and adhesiveness to bone were prepared with PLGA and Pluronic F127 using an immersion precipitation method. The porous PLGA/Pluronic F127 membranes were fabricated by immersing the PLGA/Pluronic F127 mixture solution (in tetraglycol) in a mold into water. The PLGA/Pluronic F127 mixture was precipitated in water by the diffusion of water into PLGA/Pluronic F127 mixture solution. It was observed that the membrane has an asymmetric column-shape porous structure. The top surface of the membrane (water contact side) had nano-size pores (approx. 50 nm) which can effectively prevent from fibrous connective tissue invasion but permeate nutrients, while the bottom surface (mold contact size) had micro-size pores (approx. 40 microm) which can improve adhesiveness with bone. From the investigations of mechanical property, water absorbability, model nutrient permeability and preliminary in vivo bone regeneration, the hydrophilized porous PLGA/F127 (5 wt%) membrane seems to be a good candidate as a GBR membrane for the effective permeation of nutrients and osteoconductivity, as well as good mechanical strength to maintain a secluded space for bone regeneration.     

Asymmetrically porous PLGA/Pluronic F127 membrane for effective guided bone regeneration

Porous guided bone regeneration (GBR) membranes with selective permeability, hydrophilicity and adhesiveness to bone were prepared with PLGA and Pluronic F127 using an immersion precipitation method. The porous PLGA/Pluronic F127 membranes were fabricated by immersing the PLGA/Pluronic F127 mixture solution (in tetraglycol) in a mold into water. The PLGA/Pluronic F127 mixture was precipitated in water by the diffusion of water into PLGA/Pluronic F127 mixture solution. It was observed that the membrane has an asymmetric column-shape porous structure. The top surface of the membrane (water contact side) had nano-size pores (approx. 50 nm) which can effectively prevent from fibrous connective tissue invasion but permeate nutrients, while the bottom surface (mold contact size) had micro-size pores (approx. 40 μm) which can improve adhesiveness with bone. From the investigations of mechanical property, water absorbability, model nutrient permeability and preliminary in vivo bone regeneration, the hydrophilized porous PLGA/F127 (5 wt%) membrane seems to be a good candidate as a GBR membrane for the effective permeation of nutrients and osteoconductivity, as well as good mechanical strength to maintain a secluded space for bone regeneration.     

Development of perforated microthin poly(ε-caprolactone) films as matrices for membrane tissue engineering

The design and fabrication of thin films based on bioresorbable polymers such as poly(εcaprolactone) (PCL) has been the focus of a part of current biomedical research, especially as matrices for membrane tissue engineering. We have successfully developed perforated microthin PCL membrane for this purpose. Two critical issues are the control of moisture permeability and understanding the degradation of PCL microthin film. In order to increase the moisture permeability, PCL films were biaxially stretched to a thickness of 10 ± 3 μm and perforated with uniform array of holes (180-275 μm) using a Sony Robotic system. After perforation, the water vapour transmission rate was increased by 50% to a value of 47.6 ± 2.7 g/h per m². Accelerated hydrolytic degradations were performed in 5 M NaOH. The degraded samples were characterised for changes in weight, surface morphology, mechanical properties, crystallinity and molecular weight. Hydrolytic degradation commenced with random chain scission of backbone ester bonds on the film surface and followed by loss of material due to surface erosion. In general, the perforated films degraded faster than the unperforated microthin films. Scanning electron microscopic images showed that surface erosion led to extensive formation of micropores, microcracks and increased in surface roughness.