不同长度多壁碳纳米管的细胞毒性

利用梯度密度离心法分离得到不同长度的多壁碳纳米管(multi-walled carbon nanotubes,MWCNTs),通过CCK-8、乳酸脱氢酶(lactate dehydrogenase,LDH)检测及4′-6-diamidino-2-phenylindole(DAPI)染色等方法测定细胞活力和形态,研究和评价不同长度的多壁碳纳米管对神经干细胞产生的生物学效应.研究结果显示,在质量浓度不高于100μg/mL的条件下,多壁碳纳米管对神经干细胞的活性影响与尺寸有一定相关性,但没有表现出明显毒性.研究结果进一步丰富碳纳米管生物学效应毒性评价,有利于促进碳纳米管的应用研究.     

纳米银与富里酸对AL细胞增殖及产生RNS/ROS的影响

利用ALamar Blue法和RNS/ROS荧光特异性探针,探讨不同浓度纳米银(nAg,0.1~5μg·mL~(-1))、银离子(Ag+,0.01~0.5μg·mL~(-1))及纳米银与富里酸(FA,10μg·mL~(-1))协同作用对人鼠杂交瘤(AL)细胞增殖及活性氮/活性氧自由基产生的影响及在这一过程中的作用.结果显示:在低浓度(小于等于1μg·mL~(-1))情况下,nAg对AL细胞的毒性作用主要来自于nAg释放的银离子(Ag~+),Ag~+通过诱导胞内RNS的产生,进而产生增殖抑制作用;在高浓度(5μg·mL~(-1))情况下,nAg对AL细胞的毒性主要来自于Ag~+诱导的RNS和nAg本身诱导的ROS二者共同的作用.模拟水环境中存在的FA(10μg·mL~(-1))能够显著降低nAg和Ag~+对AL细胞增殖的抑制作用,并且能显著降低nAg和Ag~+引起的A_L细胞内RNS和ROS的升高作用.     

多壁碳纳米管/聚丙烯酸复合材料的制备及表征

采用化学气相沉积法(CVD)制备多壁碳纳米管(MWNTs),并用酸纯化多壁碳纳米管(MWNTs).为了改进碳纳米管在聚合物中的性能,采用化学修饰法制备了多壁碳纳米管/聚丙烯酸(MWNTs/PAA)复合材料,并用扫描电镜(SEM)、透射电镜(TEM)和红外光谱(FT-IR)对其进行了表征.实验结果表明,聚丙烯酸能均匀地包覆在碳纳米管表面,而且多壁碳纳米管/聚丙烯酸复合材料能很好地分散在水和苯丙乳液中.     

双酚A激活雌激素受体与NF-κB信号通路促HepG2增殖的作用研究

研究了双酚A(BPA)对肝癌细胞HepG2增殖的影响及其分子机制。通过MTT实验发现,在环境浓度BPA(1×10-8 mol/L)暴露下,人肝癌HepG2细胞增殖显著升高[(156±2.48)%]。Western blotting和实时定量PCR结果显示,环境浓度的BPA处理HepG2细胞24h,细胞中NF-κB以及其下游相关炎症因子IL-1β、TNF-α的转录均明显上调。免疫荧光染色结果显示,BPA处理导致HepG2细胞内ROS显著上升;而ROS抑制剂NAC及雌激素受体抑制剂ICI 182 780均可有效抑制由BPA引起的细胞增殖和胞内p65上升。研究结果表明,BPA通过激活HepG2细胞中的雌激素受体诱导了细胞ROS的产生,随后引起细胞内炎症因子表达上调,促进细胞增殖。     

碳纳米管与四溴二苯醚复合对斑马鱼胚胎急性发育毒性研究

实验探究了四溴二苯醚(BDE-47)与多壁碳纳米管(MWCNTs)复合暴露对斑马鱼胚胎的联合发育急性及细胞凋亡.实验设置不同浓度的BDE-47与MWCNTs复合暴露溶液以及两种物质相应的单独暴露溶液.分别考察暴露96 h胚胎的急性发育毒性、96 h幼鱼细胞凋亡.结果表明:BDE-47与MWCNTs共存条件下,与单独BDE-47暴露相比,胚胎/幼鱼的存活率与孵化率显著下降、心率减慢、畸形率显著上升.由此我们可以得出MWCNTs能够加剧BDE-47对斑马鱼胚胎的毒性.     

不同预处理对多壁碳纳米管储氢性能的影响

研究了经不同预处理后多壁碳纳米管的储氢性能.结果表明:多壁碳纳米管的吸附量在0～12 MPa范围内有一个极大值,极值点的压力和吸附量与样品的种类,处理方法等密切相关;不同量不同碱金属的掺杂对多壁碳纳米管吸附的影响稍有不同;加热活化对提高多壁碳纳米管的吸附量很有效,常温下,在将近9 MPa的平衡压力下,可以达到4.48%...     

1-硝基芘和苯并[a]芘对人肺上皮A549细胞的联合细胞毒性

1-硝基芘(1-nitropyrene,1-NP)是柴油车尾气中检测浓度最高的硝基多环芳烃.以1-NP为主体,人肺上皮A549细胞为研究对象,探讨了1-NP和苯并[a]芘(benzo(a)pyrene,B[a]p)的联合细胞毒性及其对DNA的损伤.联合染毒实验结果表明:当B[a]p和1-NP同时作用于A549细胞时,B[a]p能明显减弱由1-NP造成的细胞增殖抑制和细胞内活性氧簇(reactive oxygen species,ROS)水平升高,但对DNA的损伤与1-NP单独染毒组相近;利用B[a]p预染毒A549细胞24 h,能明显减弱由1-NP造成的细胞增殖抑制和ROS水平升高,但对DNA的损伤加剧.以上结果说明,1-NP和B[a]p联合作用可能是通过抑制ROS的生成来降低对细胞增殖的抑制,但所造成的对DNA损伤的加剧可能是通过其他的作用途径.     

线粒体氧自由基和衰老的研究进展

综述了线粒体作为细胞呼吸和氧化的中心,也是产生氧自由基(ROS)的重要场所,线粒体ROS的产率与衰老的速率呈正相关;ROS能对mtDNA产生氧化伤害导致mtDNA突变,mtDNA突变的增加能加速衰老进程,抗氧化剂和热量限制(CR)都能影响细胞的衰老,但有着不同的机制;最后还讨论自由基导致衰老学说所面临的困难与挑战,展望了对衰老本质的探索。     

一种可能的单壁碳纳米管成核机制

0 引言 单壁碳纳米管是当前科学研究的热点,虽然单壁碳纳米管的制备技术已有很大的进展,但人们对其生长机制却仍然了解甚少.单壁碳纳米管可以用电弧放电(arc discharge)[1],激光熔融(laser ablation)[2]和化学气相淀积(chemical vapour deposition)[3]等方法产生,与多壁碳纳米管制备方法最大的不同点在于单壁碳纳米管的形成必须使用催化剂.     

碳纳米管吸附还原溴酸盐研究

以单壁碳纳米管(single walled carbon nanotubes,SWCNTs)和多壁碳纳米管(multiwalled carbon nanotubes,MWCNTs)作为原料,经过硝酸处理后分别在800℃、950℃和1100℃下焙烧得到S-800、S-950、S-1100、M-800、M-950和M-1100系列吸附材料.测试其对饮用水中溴酸盐的吸附性能,结果发现反应48h后单壁碳纳米管对0.5mg·L~(-1)、1.0mg·L~(-1)和5.0mg·L~(-1)溴酸盐去除率高于多壁碳纳米管;随着焙烧温度升高,碳纳米管对溴酸盐的去除率显著增强.此外还发现,经过4次循环使用后碳纳米管去除溴酸盐的效率无明显降低.为了探讨碳纳米管对溴酸盐的吸附去除机制,对制备的材料进行了氮气吸脱附Brunauer-Emmett-Teller(BET)、Transmission electron microscopy(TEM)、X-ray diffraction(XRD)、Raman spectroscopy(Raman)、X-ray photoelectron spectroscopy(XPS)、Zeta电位等性质表征.结果发现反应过后碳纳米管表面氧元素含量显著增加,通过不同温度焙烧得到的材料其等电点也有显著差异.     

6-取代1-氮杂苯并蒽酮衍生物的合成及抗肿瘤活性研究

以DNA双螺旋结构为靶点,设计合成了一系列新的6-取代的氧化异阿朴菲生物碱衍生物3a～3e。所有化合物的结构均用ESI-MS,1HNMR和元素分析确认。运用紫外吸收光谱研究了氧化异阿朴菲生物碱衍生物与小牛胸腺DNA(ctDNA)的相互作用。用MTT法评价衍生物对HepG2、SGC-7901、SW480、786-O和NCI-H460 5种肿瘤细胞的毒性。光谱研究结果表明衍生物能与ctDNA发生嵌插结合作用,细胞毒性测试表明衍生物具有中等强度的抗肿瘤活性。     

In fl uence of the extraction parameters on the cytotoxicity test results of Mg materials

Recently more and more researchers query the predictability of cytotoxicity results of biomedical Mg alloys obtained according to ISO 10993 due to significant difference between in vitro and in vivo corrosion. This study aimed to observe the influence of different extraction parameters(time, volume/surface ratio and medium composition) on cytotoxicity results and illustrate whether more predictable results could be obtained by adjusting the extraction parameters. The results showed that longer extraction time and smaller extraction volume/surface ratio improve the sensitivity of screening Mg materials by making inferior Mg materials release relatively more ions to the extract; and more predictable results could not be obtained by the way of simply adding bovine serum albumin(BSA) into the extraction medium to the same level in vivo or simply using fetal bovine serum(FBS) directly as extraction medium, since BSA and FBS accelerated the corrosion of Mg materials during extraction and they affected the cells’ health states during the test. In order to get more predictable results, in our opinions, it is necessary to establish a database of primary cells’ hazards(metal ions, p H and H2gas) tolerance and a set of in vitro corrosion test with high similarity in vivo, which is very difficult to realize now however.     

中空介孔硅球对血管内皮细胞的细胞毒性

通过细胞增殖实验和乳酸脱氢酶释放实验,流式细胞术,透射电镜及电感耦合等离子体发射光谱仪检测等方法,证实HMSN在浓度超过62.5 μg/mL时,会对人脐静脉血管内皮细胞产生毒性,半抑制浓度约为150 μg/mL.高浓度下HMSN导致细胞增殖抑制和乳酸脱氢酶释放,使细胞周期阻滞在G1期,并最终诱导细胞坏死.同时发现HMS...     

In vitro degradation and biocompatibility of Mg-Nd-Zn-Zr alloy

In this study,in vitro degradation and biocompatibility of Mg-Nd-Zn-Zr(NZK) alloy were investigated to determine its suitability as a degradable medical biomaterial.Its corrosion properties were evaluated by static immersion test,electrochemical corrosion test,scanning electron microscopy(SEM),and energy dispersive spectroscopic(EDS) analysis,and in vitro biocompatibilities were assessed by hemolysis and cytotoxicity tests.Pure magnesium was used as control.The results of static immersion test and electrochemical corrosion test in simulated body fluid(SBF) demonstrated that the addition of alloying elements could improve the corrosion resistance.The hemolysis test found that the hemolysis rate of calcium phosphate coated NZK alloy was 4.8%,which was lower than the safe value of 5%.The cytotoxicity test indicated that NZK alloy extracts did not significantly reduce MC3T3-E1 cell viability.Hemolysis test and cytotoxicity test display excellent hemocompatibility and cytocompatibility of NZK alloy in vitro.Our data indicate that NZK alloy has excellent biocompatibility and thus can be considered as a potential degradable medical biomaterial for orthopedic applications.     

在Hep G2细胞中利用siRNA沉默GFP基因的实验探讨

目的:通过探讨小分子双链RNA(siRNA)通过RNA干扰(RNAi)机制沉默肝癌细胞株Hep G2荧光素报告基因GFP的各项生物学指标,为进一步实验和临床研究提供依据.方法:通过体外实验,对siRNA和siRNA脂质体的稳定性和细胞毒性进行评估;通过荧光标记技术,研究不同时间siRNA脂质体的转染效率;通过荧光显微镜下观察转染细胞和RT-PCR检测靶基因mRNA表达,确定不同种类、形式、剂量的siRNA对靶基因的沉默效能.结果:在空白培养液中,siRNA和siRNA脂质体可稳定至4h,在5%血清中2～4h后明显降解;100nM的siRNA和siRNA脂质体无明显细胞毒性;siRNA脂质体转染细胞株的效率随时间不同而不同,4h可达90%;非特异性siRNA/脂质体无沉默靶基因表达作用,特异性siRNA/脂质体对靶基因的沉默作用在一定范围内随剂量升高(20nM、50nM、100nM)而升高.结论:siRNA的稳定性可满足实验需要,且无明显细胞毒性,特异性siRNA转染肝癌细胞株能有效抑制靶基因表达,用脂质体转染可提高转染效率.siRNA通过RNAi机制沉默靶基因表达,为肿瘤的治疗和基础研究提供了新的工具和思路.     

Specific targeting of cytotoxic T cells by anti-T3 linked to anti-target cell antibody

The specificity of cytotoxic T lymphocytes (Tc) cells is conferred by an antigen-specific receptor, Ti, which in humans is physically associated with an invariant cell-surface glycoprotein, T3. Monoclonal antibodies specific for either T3 and Ti are able to elicit a variety of T-cell responses such as lymphokine production, mitogenesis and cytotoxicity. For example, human Tc cells lyse anti-T3-expressing hybridoma cells, but not cells of other specificity, presumably because anti-T3 on the hybridoma cells binds to T3 on the Tc cells and triggers lysis. Here, we have adapted approaches used in a different cytotoxic effector system, antibody-dependent cellular cytotoxicity (ADCC), to alter the specificity of Tc cell. Studies of ADCC showed that heteroaggregates containing anti-Fc receptor (Fc gamma R) antibody cross-linked to a second antibody bind to Fc gamma R on ADCC effectors and cause them to kill target cells bearing antigen recognized by the second antibody. The present studies use anti-T3-containing heteroaggregates to re-target human Tc cells to cells for which we have appropriate antibodies, including xenogeneic tumour cells and chicken erythrocytes. These results extend previous observations on the role of T3 in triggering cytotoxicity and suggest that effector cell re-targeting could be used for in vivo treatment of neoplasms and other pathogens that express distinctive surface antigens.     

壳聚糖多孔支架的制备与生物学性质

用一种蛋白改性壳聚糖,通过冷冻干燥方法制备三维多孔支架,对支架材料的细胞毒性、贴壁率和细胞增殖等生物学特性进行评价.结果显示,采用-20,-70,-196 ℃不同温度预冻后冻干,可以制成孔结构不同的支架材料.通过冻干法制备的蛋白改性壳聚糖多孔支架对细胞没有毒性,L929细胞和人成纤维细胞可以在支架表面和内部正常生长和增殖,角质细胞在材料表面可以正常老化、角质化.     

白桦树皮提取物的抗腹水型肿瘤作用及对腹腔巨噬细胞功能的影响

利用体内荷腹水瘤模型 ,采用中性红吞噬法、染料释放法、Griess法和放射性释放法研究白桦树皮提取物 ( Extraction of Betula Platyphylla,EBP)在体内抗腹水型 S1 80和艾氏腹水癌以及对腹腔巨噬细胞功能的影响 .结果表明 ,EBP可明显延长荷腹水型 S1 80和艾氏腹水癌小鼠的生存期 ;巨噬细胞吞噬功能及分泌肿瘤坏死因子 ( TNF)和一氧化氮的功能明显增强 ,其细胞毒活性亦明显增加 ( p<0 .0 5)     

Effects of L-lactic acid and D,L-lactic acid on viability and osteogenic differentiation of mesenchymal stem cells

Poly(lactic acid) (PLA) and other aliphatic polyesters containing the unit of lactic acid are very popular biodegradable materials. While the degradation products, lactic acids, have been worried to bring with negative influence on biocompatibility, the focused experimental studies are less reported. This study is aimed at an in vitro examination of cytotoxicity of both L-lactic acid and D,L-lactic acid. Mesenchymal stem cells (MSCs) derived from rat bone marrow are employed to test the cytotoxicity of the lactic acids. Considering that the addition of lactic acids not only introduces lactate groups but also alters medium pH and ion strength, these three candidate effects are examined in a decoupled way by setting different comparison groups. The results confirm that the change of medium pH is the predominant factor. It has also been found that D-lactate is more cytotoxic than L-lactate at high concentrations. Yet, either L-or D,L-lactic acids seem acceptable in most of medical applications, because the cytotoxicity is significant only when the concentrations are as high as 20 mmol/L for both of them.     

Antiviral activities of extracts from Hong Kong seaweeds

We extracted six Hong Kong brown seaweed species with hot water for their antiviral properties. The cytotoxicity and antiviral activity of these extracts were tested by MTT [3-（4,5-dimethylthiazol-2-yl）-2,5-diphenlytetrezolium bromide] method, cytopathic effect reduction assay, and plaque reduction assay. The antiviral effect was further determined by flow cytometric analysis. The results showed that most of these extracts inhibited the propagation of herpes simplex virus types 1 and 2 （HSV-1 and HSV-2） standard strains with very low cytotoxicity to the host cells. The extracts ofHydroclathrus clathratus and Lobophora variegata showed more potential anti-HSV activities than the extracts of the other four seaweeds. They also had moderate antirespiratory syncytial virus （RSV） activities but could not inhibit influenza A virus. Hydroclathrus clathratus was further extracted by diluted acid and alkali and the antiviral effects of the extracts were also detected. The result showed that the hot water extract contained the main carbohydrate components that exhibited the antiviral activities against various strains of HSV, including the acyclovir-resistant strain. HI-3, a compound fractionated from this hot water extract, showed a dose-dependent anti-HSV activity in flow cytometric analysis and plaque reduction assay.