温度/pH双重荧光响应型水溶性聚合物的合成及在细胞成像中的应用

本文设计并合成了一种基于荧光素和聚乙二醇(PEG)的新型水溶性双重敏感型荧光聚合物材料,以改善荧光素有机小分子在应用中水溶性和生物相容性差、易脱落等缺陷。首先以荧光素为光学基团与环氧氯丙烷反应,合成含有活性环氧环基团的3-环氧丙氧基荧光素(EFlu),然后通过开环反应将EFlu键合到聚乙二醇(PEG)链端,制备得到具有良好水溶性的荧光聚合物(PEG-EFlu)。通过核磁共振、红外光谱和凝胶渗透色谱对EFlu和PEG-EFlu的结构进行表征,通过紫外-可见吸收光谱和荧光光谱测得其吸收-发射光谱和温度/pH双重荧光响应特性。测试结果表明PEG-EFlu水溶液在520 nm附近发射较强荧光,荧光量子产率为0.26,且荧光强度随环境温度的升高而下降。同时,PEG-EFlu水溶液的吸收和荧光强度均随环境pH的升高而增强,吸收波长发生明显红移,可表现出对温度和pH双重敏感响应特性。此外,通过细胞毒性以及细胞成像实验研究了PEG-EFlu的生物应用效果。细胞毒性实验结果显示:经PEG-EFlu染色后的细胞存活率均保持在95%以上,证明该荧光聚合物的低细胞毒性。清晰的荧光成像效果表明PEG-EFlu是一种潜在的生物成像剂,因此有望作为一种敏感响应型生物功能高分子材料应用于细胞示踪和检测等领域。     

吞噬二氧化硅微粒对HepG2细胞黏附和迁移的影响

通过Stber溶胶-凝胶法制备了掺杂荧光染料的二氧化硅微粒.透射电子显微镜表征其直径分别为80、160和500nm.在荧光显微镜下观察HepG2细胞对不同尺寸微粒的吞噬并采用流式细胞仪研究了微粒进入细胞的途径.检测了二氧化硅微粒的细胞毒性,通过划痕修复实验、细胞黏附和Transwell细胞迁移实验研究了吞噬二氧化硅微粒对细胞黏附和迁移能力的影响.实验结果表明,HepG2细胞主要通过网格蛋白介导的胞吞途径对二氧化硅微粒进行吞噬,4℃培养和叠氮化钠处理都会抑制胞吞的效率.在浓度为0～200μg/mL范围内,直径为80nm的二氧化硅微粒会对细胞造成浓度依赖的细胞毒性,而直径为160nm和500nm的二氧化硅微粒没有对细胞存活率造成明显的影响.但是,吞噬三种尺寸的微粒后,细胞的黏附和迁移能力都有较明显的下降,推测原因可能是由于胞吞过程对细胞骨架造成了损伤.     

一种光功能有机纳米粒子的制备及细胞毒性评价

合成了一种具有双光子荧光探针功能的有机纳米粒子2,5,2',5'-(4'-N,N-二苯胺苯乙烯基)联苯(DPA-TSB), 并研究其细胞毒性. 利用水溶性四氮唑(WST-1)法、 乳酸脱氮酶(LDH)法和流式细胞术检测了胃癌细胞吞噬纳米粒子后的生理活性. 研究结果表明, 在纳米粒子浓度小于12 μg/mL时, 胃癌细胞仍表现出较好的生理活性, 表明该纳米粒子是一种具有较好生物安全性的光功能有机纳米粒子.     

功能化硅壳荧光纳米粒的细胞吞噬研究

合成了氨基聚酰胺-胺(PAMAM(G1.0))和酯基(PAMAM(G1.5))功能化的两种硅壳荧光纳米粒,通过透射电镜(TEM)、纳米粒度及动电位测定仪(zeta电势)、傅立叶红外光谱仪(FTIR)和热失重分析仪(TGA)进行表征;通过透射电镜(TEM)、共聚焦显微镜(CLSM)、细胞计数试剂盒(CCK-8)实验、流式细胞计数法评价两种硅壳荧光纳米粒进入9L细胞能力的大小、在细胞内的分布情况以及细胞毒性.TEM分析表明,修饰的硅壳纳米粒大小约为60 nm左右,pH=7.4,氨基功能化的纳米粒zeta电势为+19.08,酯基功能化的为-9.01;FTIR和TGA实验进一步证明两种纳米粒被氨基和酯基的功能化.TEM和CLSM结果表明纳米粒主要存在细胞浆中,且能被溶酶体吞噬.CCK-8结果显示两种纳米粒的浓度高达1 mg/mL时仍无明显的毒性作用,且有促细胞增殖作用.流式细胞计数结果表明,细胞摄取纳米粒呈浓度和时间依赖性,氨基比酯基修饰的纳米粒更易进入细胞.     

基于AIE效应的多重刺激响应性聚合物纳米微球的制备及其细胞示踪应用

基于AIE分子和智能响应性聚合物构筑的纳米材料,具有优良的AIE发光性能、环境刺激响应性和生物相容性,已在生命科学领域展现出诱人的应用前景. 本研究通过ATRP活性聚合方法, 以合成的TPE-BIB为引发剂, 引发具有多刺激响应特性的N-[2-(二乙氨基)-乙基]丙烯酰胺单体聚合, 成功制备具有温度/pH/CO₂三重响应性的两亲性聚合物: TPE-g-PDEAEAM, 并自组装形成约200 nm的纳米微球. 研究表明: 这种聚合物纳米粒子具有优良的水溶性、单分散性、稳定性及优异的AIE发光特性. 其相转变温度为60 ℃, 溶液荧光对环境温度、pH及CO₂均表现出快速敏感响应性能. 同时, 该纳米粒子表现出低细胞毒性, 能够有效示踪HeLa细胞增殖至11代以上, 有望作为一种活细胞荧光示踪探针材料.     

多壁碳纳米管诱导A549细胞氧化应激与去极化线粒体膜电位

以人肺上皮细胞系A549为模型细胞, 探讨多壁碳纳米管的细胞毒性效应及其机制. A549细胞暴露于不同浓度(0~300 μg/mL)的多壁碳纳米管后, 用MTT比色法检测细胞活力和Hoechst 33342染色法观察细胞形态; 用活性氧(ROS)敏感探针2',7'-二氯荧光素二乙酸酯(DCFH-DA)结合流式细胞仪检测细胞内ROS水平; 用荧光探针JC-1结合激光共聚焦显微镜检测细胞线粒体膜电位ΔΨm的变化; 用免疫荧光和蛋白印迹法检测细胞氧化应激敏感蛋白血红素氧合酶-1(HO-1)的表达水平. 结果表明, 多壁碳纳米管可引起A549细胞活性降低、细胞内活性氧ROS过量产生以及谷胱甘肽GSH含量下降, 诱导细胞氧化应激效应; 抗氧化剂N-乙酰半胱氨酸(NAC)抑制多壁碳纳米管诱导的A549细胞内ROS的产生. 多壁碳纳米管处理A549细胞2 h后, 诱发细胞线粒体膜电位下降; 多壁碳纳米管诱导细胞氧化应激的同时伴有适应性应激蛋白HO-1的上调表达. 结果表明, 细胞氧化应激和线粒体膜电位去极化可能是多壁碳纳米管诱导A549细胞毒性效应的重要机制.     

基于亚甲基蓝的水体急性毒性快速检测方法研究

水体急性毒性的快速检测对保障用水安全至关重要。本研究以荧光假单胞菌为毒性检测的受试体,以细胞膜受损为毒性响应机理,建立了一种新颖的基于亚甲基蓝的水体急性毒性快速检测方法。在本方法中,亚甲基蓝可以对细胞膜受损的细胞进行染色,而不能对细胞膜结构完整的细胞进行染色,因此,当有毒性物质存在并对细胞膜产生破坏时,溶液中的亚甲基蓝会进入细胞对细胞进行染色,从而降低溶液中的亚甲基蓝浓度。通过光谱法检测溶液中亚甲基蓝浓度的变化,就可以实现对水体急性毒性的快速检测。实验结果表明,本方法对3,5-二氯苯酚(DCP)、As3+和Hg2+的最低响应浓度分别为1.6,12.5和3.2 mg/L,对DCP的最低响应浓度比商业化仪器Baroxymeter低。本方法操作简单,检测快速,结果可靠,在水体急性毒性的检测和监测领域具有很好的应用前景。     

细胞内转运载体超支化聚砜胺及其生物相容性

通过制备超支化聚砜胺-异硫氰酸荧光素聚合物(PSA-FITC), 研究其生物相容性、肿瘤细胞对其内吞作用和在正常小鼠体内的生物分布, 以探讨PSA作为载体进行药物和基因体内输送的可行性. 在碱性条件下共价结合PSA与FITC, 形成荧光标记聚合物(PSA-FITC)后测定聚合物中FITC含量. 在不同时间点, 通过流式细胞术检测细胞对聚合物的内吞作用; 正常balb/c裸鼠尾静脉注射PSA-FITC 24 h后, 用小动物活体荧光成像系统研究各脏器聚合物分布. 不同浓度PSA与3T3小鼠成纤维细胞及KB人口腔上皮肿瘤细胞分别孵育24, 48, 72 h后, 通过MTT法测得其生物相容性. 结果表明, PSA生物相容性良好, 72 h的细胞半抑制浓度大于1 mg/mL. 细胞摄入PSA-FITC高效快速, 3 h阳性细胞百分含量为99.24%±1.03%, 且具有时间依赖性. 在正常小鼠体内, PSA在各主要脏器或组织中无明显特异性浓聚. 超支化聚砜胺具有明显生物低毒性和高效细胞内转运特点. 由于其表面功能基团容易改性, 作为载体, 通过连接结合配体或抗体, 在肿瘤的主动靶向治疗中具有广阔的应用前景.     

海洋珍珠生物提取液对人宫颈癌Siha细胞增殖与凋亡作用的影响

为探讨海洋珍珠生物提取液对宫颈癌Siha细胞株增殖和凋亡的影响,采用MTT法检测了细胞增殖情况,在流式细胞仪用Annexin V和PI双染检测了细胞的凋亡率,PI单染法测定了细胞周期,Hoechst 33258/PI荧光染色法观测了Siha细胞的形态学改变,RT-PCR法测定了宫颈癌Siha细胞株内Bcl-2,Bax基因表达。结果表明,海洋珍珠生物提取液在一定质量浓度范围内,以浓度依赖性的方式抑制宫颈癌Siha细胞的生长(P0.05);以0,6,30和60μg/mL海洋珍珠生物提取液处理细胞24 h,Siha细胞早期凋亡率分别为5%,7.1%,32.25%和31.95%,晚期凋亡比例为0.45%,2.85%,8.55%和23.2%;荧光显微镜下细胞呈现典型的凋亡性改变;RT-PCR显示海洋珍珠生物提取液处理后宫颈癌Siha细胞内的Bcl-2 mRNA表达降低,Bax mRNA表达升高。提示海洋珍珠生物提取液以浓度依赖性的方式抑制宫颈癌Siha细胞增殖,并通过降低Bcl-2 mRNA,升高Bax mRNA来诱导细胞凋亡。     

AFM研究蝙蝠葛碱对daudi细胞毒性的影响

利用原子力显微镜、CCK-8实验和流式细胞术研究了蝙蝠葛碱(dauricine)对B细胞淋巴瘤daudi细胞的细胞毒性。蝙蝠葛碱能显著抑制daudi细胞的增殖。CCK-8实验表明,细胞存活率与蝙蝠葛碱浓度存在时间依赖和剂量依赖关系。经10～50μmol/L的蝙蝠葛碱作用24 h后,daudi细胞存活率从(89.8±4.3)%降至(11.2±3.2)%;48 h后,存活率从(68.9±2.6)%降至(2.5±0.5)%。流式细胞术表明蝙蝠葛碱处理dau-di细胞24 h后,凋亡率从5.2%增至28.2%(60μmol/L)。AFM数据显示对照组细胞呈圆形,表面较光滑。经蝙蝠葛碱处理后,daudi细胞坍塌,超微结构显示细胞表面粗糙、凹凸不平。此外,经不同浓度蝙蝠葛碱作用的daudi细胞,其线粒体膜电位随着药物浓度的加大而降低。蝙蝠葛碱能显著抑制daudi细胞生长增殖。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.