In vitro biocompatibility evaluation of silk-fibroin/polyurethane membrane with cultivation of HUVECs

In order to investigate the in vitro biocompatibility of a novel polyurethane （PU） membrane modified by incorporation of superfine silk-fibroin powder （SFP）, which was prepared for small-diameter vascular grafts, with the cultivation of human umbilical vein endothelial cells （HUVECs）, PU and SFP were mixed with the ratios of 9：1, 7：3, 5：5, 3：7 （PU：SFP） to make four composite materials. Unmodified PU and polytetrafluoroethylene （PTFE） were added as control groups. CCK-8 assay was used to evaluate the cytotoxicity of these biomaterials. Data were processed using SPSS, and P〈 0.05 was considered to be statistically significant. Adherence and spreading of HUVECs on the surface of specimens was observed using direct contact cultivation. The toxicity ratings of the novel composites were grade 0-1, which is in the acceptable range. In all the experimental groups except control, SFP/PU with ratio of 1：9 had the least cytotoxicity property, and more content of SFP in the composite showed no improvement of the biocompatibility. HUVECs strongly attached to and grew on the surface of the biomaterials, and proliferated rapidly. The proliferation ability increased with increased proportion of SFP; however the cell quantity on the surface of the materials decreased when the proportion of SFP was equal to or larger than that of PU in the composite. It is concluded that this novel material has excellent cellular affinity with no cytotoxicity to HUVECs. Adding SFP gives PU better biocompatibility, while further research on optimum blend ratios is still needed.     

壳聚糖静电吸附羧基磷酰胆碱聚合物的研究

采用饥饿法聚合合成了3种不同配比的甲基丙烯酰氧乙基磷酰胆碱-甲基丙烯酸二元共聚物(poly(MPC-co-MA),PMA),并将其静电吸附在壳聚糖表面(CS-PMA)。通过动态接触角(DCA)对影响静电吸附改性的盐及聚合物组成因素进行研究。用X-射线光电子能谱(XPS)、原子力显微镜(AFM)对改性壳聚糖膜的表面元素组成、形貌进行表征,并通过血小板黏附实验对其抗凝血性能进行评价。结果表明,这种利用静电吸附的方式将磷酰胆碱聚合物吸附在壳聚糖表面,可获得具有仿细胞外层膜结构的涂层表面。与壳聚糖相比,改性后壳聚糖可以显著降低对血小板的黏附,抗凝血性能显著提高。该研究为构建仿细胞外层膜结构改善材料血液相容性提供了一种简单、便捷的方法。     

生物活性玻璃的表面修饰及其细胞相容性

采用硅烷偶联剂对生物活性玻璃(BG)进行表面修饰以改善其与高分子的亲和性。通过溶胶凝胶法制得BG, 将氨丙基三乙氧基硅烷(APTES)键连到BG表面, 采用FTIR、 TG、 激光粒度仪等对修饰前后的BG进行表征, 并通过细胞实验对材料的细胞相容性进行初步研究。结果表明, 修饰后BG的FTIR图谱上出现归属于C—H的伸缩振动吸收峰, 在DTG曲线上观察到明显的有机基团燃烧失重峰, 表明APTES接枝到生物玻璃表面; 而MC-3T3细胞增殖测定和SEM结果显示经表面修饰后的BG更有利于细胞的生长增殖。      

Synthesis,characterization r）oly [LA-co-（GIc-alt-Lys）] for and biological evaluation of nerve regeneration scaffold

A novel nerve repairing material poly [LA-co.（GIc-alt-Lys）] （PLGL） was synthesized. The viability and growth of Schwann cells （SCs） co-cultured With poly （D, L- lactic acid） （PDLLA） films （control group） and PLGL films were evaluated by MTT assay and SEM observation. Then, contact angle measurement, histological assessment and enzyme-linked immunosorbent assay （ELISA） testing on inflammatory-related cyto- kines such as IL-10 and TGF-β1 were performed. The results showed that, compared with PDLLA, PLGL films possesses better hydrophilicity, biocompatibility, degradation property and less inflammatory reaction. The present study indicated that PLGL scaffolds would meet the requirements of artificial nerve scaffold and have a potential application in the fields of nerve regeneration.     

聚合物膜燃料电池的发展状况

介绍燃料电池的工作原理、催化剂有效应用、聚合物膜电解质及燃料储存和开发     

膜面孔特征的图像分析研究

利用图像分析方法对微滤膜和超滤膜的电镜照片进行了分析,定量确定了膜孔相关的形态结构参数,并将膜孔参数与膜通量相关联.结果表明,由于微滤膜的交错立体分层结构,使得膜通量在过滤过程中随膜层厚度急剧下降.截留分子量相同或相近的超滤膜,膜孔形态参数差别很大.     

医用不锈钢的细胞膜仿生表面修饰

利用2-（甲基丙烯酰氧基）乙基-2-（三甲基氨基）乙基磷酸酯（MPC）与316L不锈钢表面上γ-氨基丙基三乙氧基硅烷（KH550）的Michael加成反应,将MPC化学接枝到不锈钢的表面．修饰表面的XPS结果证实了MPC的成功接枝,表明在不锈钢表面构建了仿细胞膜表面．体外血小板粘附实验显示,修饰表面具有明显阻抗血小板的粘附、聚集和激活性能,并具有良好的血液相容性．     

离子膜原电池法还原钛液中的三价铁

提出了离子膜原电池法还原钛液中的Fe^3 新方法。原电池的正极由铅（或铜）电极和钛液组成,负极电铁电极和酸性FeSO4溶液组成,离子交换膜作为正负两极间的隔膜,利用原电池的放电过程还原钛液中的Fe^3 。并详细地考察了温度、溶液电解液流速、膜面积等因素对还原速度的影响,实验结果表明,膜电流密度最大可达100A/m^2以上。     

反胶束法制备PEMFC用Pt-Ru／C催化剂

采用反胶柬法制备质子交换膜燃料电池（PEMFC）用Pt-Ru／C催化剂．反胶柬体系由环己烷、水、表面活性剂和正辛醇组成．研究了反胶束体系中水与表面活性剂的物质的量之比（ω）、不同类型的表面活性剂和不同还原剂等因素对Pt-Ru／c催化剂性能的影响．研究表明,采用SDS为表面活性剂,控制ω值在适宜的范围内,采用强还原剂KHB4,在室温下反应,可得到粒径小、分布均匀的Pt-Ru／c催化剂．透射电镜（TEM）测试结果表明,Pt—Ru粒子的平均粒径为3．1nm;X射线衍射（XRD）分析表明,Pt—Ru／c催化剂合金化程度高,相对结晶度为3．1;能量散射能谱（EDS）分析表明,形成的Pt和Ru的含量接近实验设定值在0．5mol／L的H2SO4以及与0．5mol／L的CH3OH混合溶液中的循环伏安测试结果表明,自制Pt—Ru／C催化剂与Johnson公司商品Pt—Ru／C催化剂的电化学性能相近。     

PSA接枝碳纳米管增强PVA/PSA共混物薄膜的微结构与性能

通过溶液浇铸及化学交联,制备了聚(苯乙烯磺酸钠-co-丙烯酸)接枝碳纳米管(PSA-g-MWNT)增强聚乙烯醇(PVA)/PSA复合膜,着重研究了改性碳纳米管对复合膜的微观结构、力学性能、电导率、离子交换容量(IEC)和吸水率的影响。结果表明,当PVA与PSA质量比为2∶1时,PVA/PSA共混物薄膜的综合性能最佳。接枝在MWNT表面的PSA提高了MWNT与PVA/PSA共混物之间的相容性,实现了MWNT对PVA/PSA薄膜的同时增强、增韧。随着PSA-g-MWNT含量的增加,PVA/PSA/PSA-g-MWNT复合膜的电导率显著提高,IEC值也呈升高的趋势。     

新型燃料电池质子交换膜的研究进展

由于当前所使用的质子交换膜材料存在成本高、无法高温操作和不够环保等缺点,开发新型的成本低、性能高的质子交换膜越来越引起人们的重视．对于新型质子交换膜的研制主要体现在两个方面,一个是对于全氟磺酸型膜的改进和增强,包括加入支撑材料或掺杂增强材料等方法;另一个是彻底抛开全氟树脂,开发新型的质子交换膜材料,其中包括直接磺化、直接聚合、接枝、掺杂等制备方法,简要评述了这些方法的优缺点和这些膜材料的性能,并附以实例说明．     

The development of graphene-based devices for cell biology research

Graphene has emerged as a new carbon nanoform with great potential in many applications due to its exceptional physical and chemical properties. Especially, graphene and its derivatives are also gaining a lot of interest in the biomedical field as new components for biosensors, tissue engineering, and drug delivery. This review presents unique properties of graphene, the bio-effects of graphene and its derivatives, especially their interactions with cells and the development of graphene-based biosensors and nanomedicines for cancer diagnosis and treatment.     

基于机理模型的质子交换膜燃料电池动态特性分析

详细分析了质子交换膜燃料电池(PEMFC)的机理模型,在此基础上运用Matlab的Simulink仿真工具建立PEMFC电堆的动态仿真模型.通过所建立的电堆动态仿真模型,就能够研究主要运行参数对电堆动态特性输出的影响.当电堆输出电流出现阶跃变化时,仿真分析了电堆的输出电压、输出功率、消耗功率、电堆等效内阻和电堆效率的动态响应.仿真结果和已知文献的实验数据基本一致,表明建立的电堆模型是正确、可操作和有效的.该研究有助于实现对PEMFC电堆的实时分析和动态优化,为PEMFC的实际应用提供了帮助.     

质子交换膜燃料电池关键材料的研究进展EI北大核心CSCD

燃料电池是一种非常有前景的新能源体系。燃料电池不使用热力发动机,利用电极和电解质界面发生的化学反应直接将燃料的化学能转换成电能,反应不受卡诺循环限制,因此,具有高的能量转换效率。在燃料电池中,质子交换膜燃料电池(PEMFC)在便携式设备、交通运输以及固定装置领域具有重要的应用前景。然而,目前的PEMFC还存在一些问题,主要包括高成本、功率不足、稳定性差等问题,限制了其大规模商业化应用。这些问题的根本原因在于PEMFC中阴极催化剂、气体扩散层、质子交换膜和双极板等关键材料的成本和性能还不能满足PEMFC商业化的要求。要实现PEMFC的大规模应用,需要开发先进的阴极催化剂、气体扩散层、质子交换膜和双极板等关键材料。针对PEMFC对低成本、高性能先进材料的需求,本文综述了阴极催化剂、气体扩散层、质子交换膜和双极板等关键材料的研究进展以及应用面临的问题,并指出了未来的发展方向:加强铂合金催化剂以及金属-氮-碳(M-N-C)化合物催化剂的规模化制备工艺的探索;制备兼具高质子传导率和优异力学性能的质子交换膜;详细研究改性气体扩散层在不同的工况条件下对PEMFC性能的影响;开发具有优良耐蚀性和导电性的涂层或新型金属材料用于双极板。     

响应面法优化PSSA/PVA共混膜催化酯化制备生物柴油

采用响应面法考察聚苯乙烯磺酸(PSSA)/聚乙烯醇(PVA)共混型催化膜催化酯化制备生物柴油工艺中催化膜用量、醇油质量比、反应时间和反应温度及其交互作用对酯化率的影响,结果发现,各因素对转化率影响顺序为:醇油比＞催化剂用量＞反应温度＞反应时间;同时,醇油比与催化剂量的交互作用对转化率的影响最强,而与反应时间相关的交互作...     

Preparation of anion-exchange membrane by plasma polymerization and its use in alkaline fuel cells

A 4-vinylpyridine-based anion-exchange membrane was prepared by plasma polymerization. Scanning electron microscope and Fourier transform infrared spectroscopy showed that the membrane had uniformly thin and highly cross-linked form. The membrane was ca. 10 μm thick and its effective resistance was remarkably lower than that of a commercial membrane. In addition, modification of carbon-supported platinum with the plasma-membrane enhanced hydrogen oxidation at the gas diffusion electrode due to an increase in the triple-phase boundary. Therefore, it is shown that plasma treatment is very useful for improving the performance of alkaline fuel cell using anion-exchange membrane.     

Photoelectrochemical behaviour of Cdln2S4 films deposited by pulse electrodeposition using non-aqueous electrolyte

Cdln2S4 films were deposited by the pulse electrodeposition technique on tin oxide-coated glass substrates, at different duty cycles in the range of 6%-50%. The deposition potential was -0.7 V vs, saturated calomel electrode （SCE） using non-aqueous di（ethylene glycol） electrolyte, XRD analysis of the films indicated polycrystalline nature. Grain size, strain and dislocation density were evaluated from the XRD data, EDX analysis of the surface composition confirms the formation of stoichiometric Cdln2S4 films, Optical studies show a direct band-gap values in the range of 2.14-2.23 eV for the films deposited at different duty cycles. Room temperature resistivity of the films was in the range of 40-21 Q.cm with the increase of duty cycle. Photoelectrochemical （PEC） solar cells constructed with the films deposited at 50% duty cycle and post-heat-treated at 500~C indicated open circuit voltage （Voc） of 0.595 V, short circuit current density （Jsc） of 6.20 mA.cm-2, fill factor （if） of 0.61, efficiency （t/） of 3.75%, series resistance （Rs） of 4Q and shunt resistance （Rsh） of 2.50kQ. Making use of the advantages of pulse electrodeposition it can be used to deposit nanocrystalline films which can be employed in optoelectronic and photovoltaic devices.     

Preparation of the acidic PVA/MMT nanocomposite polymer membrane for the direct methanol fuel cell (DMFC)

A novel nanocomposite polymer electrolyte membrane composed of PVA polymer matrix and nanosized Montmorillonite (MMT) filler, was prepared by a solution casting method. The characteristic properties of the PVA/MMT nanocomposite polymer membrane were investigated using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), atomic force microscopy (AFM), micro-Raman spectroscopy, and the AC impedance method. The PVA polymer directly blended with nanosized MMT filler (2-20 wt.%) showed good ionic conductivity, thermal, and mechanical properties. The highest ionic conductivity value for the acidic PVA/10 wt.%MMT nanocomposite polymer membrane was around 0.0368 S cm^− 1 at 30 °C. The methanol permeability (P) value was 3-4 × 10^− 6 cm² s^− 1. It was revealed that the addition of nanosized MMT fillers into the PVA matrix could markedly improve the electrochemical properties of the PVA/MMT nanocomposite membrane. In fact, the PVA/MMT nanocomposite polymer membrane appears to be a good candidate for the DMFC applications.     

超声作用下大肠杆菌细胞膜通透性的动力学模型

在合理假设的基础上运用传递理论以及普遍成立的质量守恒原理,建立了超声作用大肠杆菌膜变化的动力学模型：E（t）=（k3T-k1/）（k2＋k3）·e-（k2＋k3）·t＋（k2T-k1/k2＋k3）。基于该模型的理论模拟结果与实验结果比较表明：该动力学模型对膜变化过程具有很好的预测功能,能反映膜变化的实际过程。（E-胞内荧光素的浓度;t-时间;T-胞内外渗透物质总量;k1-细胞死亡后引起的荧光素损失速率常数;k2-荧光素从胞外渗透入胞内的速率常数;k3-荧光素从胞内渗出胞外后又反渗透入胞内的速率常数。）     

Aptamer-conjugated upconversion nanoprobes assisted by magnetic separation for effective isolation and sensitive detection of circulating tumor cells

Detection of circulating tumor cells （CTCs） plays an important role in cancer diagnosis and prognosis. In this study, aptamer-conjugated upconversion nano- particles （UCNPs） are used for the first time as nanoprobes to recognize tumor cells, which are then enriched by attaching with magnetic nanoparticles （MNPs） and placing in the presence of a magnetic field. Owing to the autofluorescence- free nature of upconversion luminescence imaging, as well as the use of magnetic separation to further reduce background signals, our technique allows for highly sensitive detection and collection of small numbers of tumor cells spiked into healthy blood samples, and shows promise for CTC detection in medical diagnostics.