表面改性的纳米Fe3O4颗粒用于抗血清快速分离纯化

采用硅烷化试剂Si(OC2H5)3C3H6NH2(APTES)对纳米Fe3O4颗粒表面进行氨基化改性后, 考察了不同浓度偶联剂戊二醛对于颗粒表面固定牛血清白蛋白(BSA)量的影响。此超顺磁性免疫铁颗粒(SPIO)加入兔抗BSA血清中特异性结合BSA抗体后, 用Gly-HCl缓冲液洗脱得到IgG。结果表明当戊二醛浓度大于10%时, 单位颗粒固定蛋白的量达到最大值约140 mg/mg, 10 min, 15 mg的SPIO即可将1 mL抗血清完全分离, 经过两次快速洗脱, 颗粒表面吸附的抗体即可得到纯化; 琼脂扩散实验表明分离后的抗体仍保持较高活性, SDS-PAGE电泳结果表明用此方法纯化后的兔抗BSA IgG纯度大于99%, 比传统的(NH4)2SO4法有了较大提高, 但纯化量并没有减少; SPIO在经过五次重复利用后仍能保持78%以上的分离效果。     

BSA与α-MnO2及δ-MnO2间的界面吸附作用

比较研究了牛血清白蛋白(BSA)与α-MnO2和δ-MnO2的界面吸附作用及其影响因素。结果表明,BSA在两种MnO2颗粒物表面有明显的吸附,且δ-MnO2比α-MnO2对BSA的吸附能力略强。pH3.8~8.0范围内,BSA在α-MnO2和δ-MnO2上的吸附率随pH的升高而减小,pH3.8条件下,α-MnO2上的吸附率为88.2%,δ-MnO2上的吸附率为94.0%。BSA在α-MnO2和δ-MnO2上的吸附量均随BSA浓度的增加而增大,吸附率随NaCl浓度的增加而减小。BSA在α-MnO2上的吸附具有很高的不可逆性,δ-MnO2上的吸附完全不可逆。吸附过程中BSA发生解螺旋作用,引起结构熵增大。     

牛血清白蛋白对Cu+与δ-MnO2间吸附平衡性质的影响

研究了溶液中牛血清白蛋白(BSA)的存在对Cu2 与δ-MnO2间吸附平衡性质的影响,旨在增进人们对Cu2 环境化学行为的认识.结果表明:BSA存在下,Cu2 在δ-MnO2表面的吸附率-pH曲线呈典型的"S"形,加入BSA使Cu2 的吸附突跃向高pH方向移动,影响程度与BSA的加入方式有关,其次序为Ⅳ(先加BSA后加Cu2 )＞Ⅲ(Cu2 和BSA同时加)≈Ⅱ((先加Cu2 后加BSA);BSA存在下,Cu2 的等温吸附线遵循Langmuir等温吸附方程,Cu2 的饱和吸附量随BSA浓度的增大而减小,并随BSA的加入方式而改变,其次序为Ⅰ(不加BSA)＞Ⅱ≈Ⅲ＞Ⅳ;Cu2 在δ-MnO2上的饱和吸附量随温度的升高而增大.在pH=3.0条件下,Cu2 在δ-MnO2上的吸附是完全可逆的,但pH=5.0的条件下,吸附是不可逆的,BSA对Cu2 的吸附可逆性没有影响.     

低浓度微囊藻毒素MC-LR对梭鱼草幼苗根系NH_4~+和H_2PO_4~-吸收特性的影响

运用营养液培养法和常规耗竭法,对低浓度(2和10μg·L~(-1))微囊藻毒素MC-LR分别处理6和12 d后梭鱼草(Pontederia cordata Linn.)幼苗根系对不同浓度NH_4~+(0.05~1.50 mmol·L~(-1))和H_2PO_4~-(0.01~0.50mmol·L~(-1))的吸收速率和吸收动力学参数的变化进行了研究。结果显示:随培养液中NH_4~+和H_2PO_4~-浓度的提高,各处理组幼苗根系的NH_4~+和H_2PO_4~-吸收速率均逐渐增大,但增幅则因MC-LR处理浓度和处理时间而异。经2和10μg·L~(-1)MC-LR短期(6 d)处理后,幼苗根系的NH_4~+和H_2PO_4~-吸收速率总体上均显著高于CK(对照,0μg·L~(-1)MC-LR)组;经长期(12 d)处理后,2μg·L~(-1)MC-LR处理组幼苗根系的H_2PO_4~-和较高浓度NH_4~+吸收速率均显著高于CK组,而10μg·L~(-1)MC-LR处理组幼苗根系的NH_4~+吸收速率降低,但其较高浓度H_2PO_4~-吸收速率仍显著高于CK组。梭鱼草幼苗根系的NH_4~+和H_2PO_4~-吸收速率与底物浓度的函数关系均符合双倒数曲线,拟合关系均在α=0.001水平上显著,但最大吸收速率(V_(max))和表观米氏常数(K_m)变化规律不同。经2和10μg·L~(-1)MC-LR处理6和12 d后,幼苗根系NH_4~+吸收的V_(max)和K_m值均高于CK组;经2μg·L~(-1)MC-LR处理6和12 d后,幼苗根系H_2PO_4~-吸收的V_(max)值高于CK组、K_m值低于CK组;经10μg·L~(-1)MC-LR处理6 d后幼苗根系H_2PO_4~-吸收的V_(max)值高于CK组、K_m值与CK组无差异,但经10μg·L~(-1)MC-LR处理12 d后幼苗根系H_2PO_4~-吸收的V_(max)值略高于CK组、K_m值明显高于CK组。说明随处理时间延长,经2μg·L~(-1)MC-LR处理后幼苗根系的NH_4~+吸收潜力提高、NH_4~+亲和力略有降低,而H_2PO_4~-吸收潜力略有降低、H_2PO_4~-亲和力略有提高;经10μg·L~(-1)MC-LR处理后幼苗根系的NH_4~+吸收潜力略有提高、NH_4~+亲和力降低,而H_2PO_4~-吸收潜力和亲和力均降低。综合分析结果表明:2和10μg·L~(-1)MC-LR处理均能够提升梭鱼草幼苗根系的NH_4~+和H_2PO_4~-吸收潜力,其中,2μg·L~(-1)MC-LR处理对其根系的NH_4~+和H_2PO_4~-吸收均具有明显的促进作用,而10μg·L~(-1)MC-LR短期处理对其根系的NH_4~+和H_2PO_4~-吸收也具有一定的促进作用。     

界面上配基种类对BSA吸附行为的影响

利用双偏振极化干涉测量仪(DPI)研究了界面上配基种类对BSA吸附行为的影响。采用3-氨基丙基三乙氧基硅烷(APTES)、3-(甲氨基)丙基三甲氧基硅烷(MAPTMS)和N,N-二乙基-3-氨基丙基三甲氧基硅烷(DAPTMS)对DPI芯片进行了修饰,利用X射线光电子能谱比较了芯片上不同配基的密度,采用原子力显微镜(AFM)和DPI对界面上BSA吸附行为进行了研究。结果表明APTES修饰界面上BSA呈饼状,高配基密度易导致BSA多位点吸附。相同偶联密度条件下BSA在DAPTMS修饰芯片的吸附量高于MAPTMS修饰芯片,但吸附层厚度一致,表明DAPTMS表面上BSA存在聚集现象;AFM扫描结果与DPI分析结果一致,证明了配基密度和种类不仅影响界面上蛋白质吸附量,而且影响蛋白质吸附密度和表面聚集行为。     

纳米羟基磷灰石表面修饰及其转染细胞的研究

目的:探讨羟基磷灰石-聚乙烯亚胺(nHA-PEI 10KD)纳米颗粒的癌细胞基因转染效率.方法:通过透射电子显微镜(TEM)观察HA-PEI(10KD)纳米颗粒的形态及粒径,Zeta电位仪测定nHA-PEI和HA在酸、碱、中性环境中的电位,用琼脂糖凝胶电泳检测nHAP-PEI(10KD)与DNA结合的能力,MTT比色法检测nHAP-PEI(10KD)对nepG2细胞的毒性,选用增强型绿色荧光蛋白质粒pEGFP1与nHA-PEI结合后,分别转染真核细胞HepG2、Hela、SW620,计算其转染率.结果:nHA-PEI(10KD)分散程度好,粒径60-80nm,在PH7.2时,Zeta电位42.87mV,能转染实验中的细胞,转然效果最好的是HepG2细胞,其次Hela、SW620,转染率高于PEI(10KD)、nHA,但低于脂质体.结论:通过阳离子PEI修饰HA,可有效将增强型绿色荧光蛋白质粒转入HepG2细胞,HA-PEI(10KD)纳米颗粒复合物有望成为基因传递的有效栽体.     

1株鞘细菌的分离筛选及对铅离子吸附条件的研究

通过单因素试验设计,探讨了不同鞘细菌添加量、初始浓度的铅离子溶液、吸附时溶液的温度和p H对鞘细菌吸附铅离子的影响。在此基础上,采用4因素3水平正交试验设计,进一步探讨鞘细菌对铅离子吸附影响的主要因素及最佳吸附组合。试验结果表明,最佳吸附组合为鞘细菌制备液添加量0.3 g/L、吸附溶液中铅离子初始浓度10 mg/L、摇床振荡吸附温度30℃以及吸附液p H 8。在此条件下,鞘细菌吸附铅离子的吸附量为3.09 mg/g,吸附率达92.74%。     

应用HA、NA、M1和M2蛋白制备H5N1高致病性禽流感病毒样颗粒

目的:应用重组杆状病毒表达系统制备由HA、NA、M1和M2蛋白组成的H5N1高致病性禽流感病毒样颗粒,为研究H5N1高致病性禽流感疫苗奠定基础。方法:构建能共表达A/chicken/Jilin/2003(H5N1)禽流感病毒血凝素(HA)和神经氨酸酶(NA)、A/PR/8/34(H1N1)流感病毒基质蛋白(M1)和离子通道蛋白(M2)的2个二元重组杆状病毒,共同感染HighFive细胞,同时表达HA、NA、M1和M2蛋白,使这4种蛋白在感染的细胞内自主组装成病毒样颗粒。经差速离心和蔗糖密度梯度超速离心收获病毒样颗粒,通过Western印迹鉴定病毒样颗粒的组成,透射电镜观察病毒样颗粒形态,血凝试验测定病毒样颗粒的活性。结果:HA、NA、M1、M2蛋白在昆虫细胞中共表达,并组装成病毒样颗粒;电镜观察到病毒样颗粒的形态与流感病毒一致,直径约80 nm;血凝试验显示该病毒样颗粒具有凝集鸡红细胞的活性。结论:应用该方法可以制备流感病毒样颗粒,为H5N1流感疫苗研究提供了可行方案。     

牛血清白蛋白对Cu^2＋与δ-MnO2间吸附平衡性质的影响

研究了溶液中牛血清白蛋白（BSA）的存在对Cu^2＋与δ-MnO2间吸附平衡性质的影响,旨在增进人们对Cu^2＋环境化学行为的认识。结果表明：BSA存在下,Cu^2＋在δ-MnO2表面的吸附率-pH曲线呈典型的“S”形,加入BSA使Cu^2＋的吸附突跃向高pH方向移动,影响程度与BSA的加入方式有关,其次序为Ⅳ（先加BSA后加Cu^2＋）〉Ⅲ（Cu^2＋和BSA同时加）≈Ⅱ（（先加Cu^2＋后加BSA）;BSA存在下,Cu^2＋的等温吸附线遵循Langmuir等温吸附方程,Cu^2＋的饱和吸附量随BSA浓度的增大而减小,并随BSA的加入方式而改变,其次序为I（不加BSA）〉Ⅱ≈Ⅲ〉Ⅳ;Cu^2＋在δ-MnO2上的饱和吸附量随温度的升高而增大。在pH=3．0条件下,Cu^2＋在δ-MnO2上的吸附是完全可逆的,但pH=5．0的条件下,吸附是不可逆的,BSA对Cu^2＋的吸附可逆性没有影响。     

BSA与α-MnO2及δ-MnO2间的界面吸附作用

比较研究了牛血清白蛋白（BSA）与α-MnO2和δ-MnO₂的界面吸附作用及其影响因素。结果表明,BSA在两种MnO₂颗粒物表面有明显的吸附,且δ-MnO₂比α-MnO₂对BSA的吸附能力略强。pH3.8~8.0范围内,BSA在α-MnO₂和δ-MnO₂上的吸附率随pH的升高而减小,pH3.8条件下,α-MnO₂上的吸附率为88.2%,δ-MnO₂上的吸附率为94.0%。BSA在α-MnO₂和δ-MnO₂上的吸附量均随BSA浓度的增加而增大,吸附率随NaCl浓度的增加而减小。BSA在α-MnO₂上的吸附具有很高的不可逆性,δ-MnO₂上的吸附完全不可逆。吸附过程中BSA发生解螺旋作用,引起结构熵增大。     

大孔吸附树脂对红车轴草异黄酮吸附分离特性的研究

通过比较14种大孔吸附树脂对红车轴草异黄酮的吸附率和解吸率,筛选出适合红车轴草异黄酮分离的树脂,并对其动态吸附特性进行研究。结果表明,AB-8树脂对红车轴草异黄酮不仅吸附量大,而且解吸率高,适合红车轴草异黄酮的分离富集。AB-8树脂分离红车轴草异黄酮的工艺参数为:上柱液浓度0.79~1.11 mg/mL,pH 4.24,流速2 BV/h。以4倍树脂床体积的80%乙醇以2 BV/h流速进行洗脱,可基本上将红车轴草异黄酮从树脂上解吸下来,异黄酮回收率为93.72%。     

Expanded bed adsorption/desorption of proteins with Streamline Direct CST I adsorbent

Streamline Direct CST I is a new type of ion exchanger with multi-modal functional groups, specially designed for an expanded bed adsorption (EBA) process, which can capture directly the proteins from the high ionic strength feedstocks with a high binding capacity. In this study, an experimental study is carried out for two-component proteins (BSA and myoglobin) competitive adsorption and desorption in an expanded bed packed with Streamline Direct CST I. Based on the measurements of the single- and two-component bovine serum albumin (BSA)/myoglobin adsorption isotherm on Streamline Direct CST I, the binding and elution conditions for the whole EBA process are selected; and then frontal analysis for a longer timescale and column displacement experiments in a fixed bed (XK16/20 column) are carried out to evaluate the two-component proteins (BSA and myoglobin) competitive adsorption and displacement on Streamline Direct CST I. Finally, the feasibility of capturing both BSA and myoglobin by an expanded bed packed with Streamline Direct CST I is addressed in a Streamline 50 column packed with 300 mL Streamline Direct CST I.     

Prediction of fertilizer phosphate requirement using the Langmuir adsorption maximum

The phosphate adsorption maximum as calculated by the Langmuir equation was used to predict the fertilizer P requirement of wheat (Triticum aestivium, cv. Caldwell) on both virgin and cultivated Decatur clay loam (clayey, kaolinitic, thermic, Rhodic Paleudult) and Hartsells sandy loam soils (fine-loamy, siliceous, thermic, Typic Hapludult). Soils with higher adsorption maximum were found to require more fertilizer P than soils with lower adsorption maximum. For soils 25% saturation of the adsorption maximum gave the optimum dry matter yield. This corresponded to equilibrium P concentration of 0.45 mg L⁻¹ for Decatur cultivated and 0.31 mg L⁻¹ for Decatur and Hartsells virgin soils for optimum dry matter yield. These values are within the range of those reported previously by other investigators working with different soils.     

Evaluation of the effect of in-bed sampling on expanded bed adsorption

An expanded bed adsorption (EBA) column (5 cm diameter) has been modified to allow the abstraction of liquid samples from various positions along the height of an expanded bed. As the adsorbent particles were fluidized, in-bed monitoring of key component concentrations during feedstock application, washing and elution was achieved by the withdrawal of liquid samples from the voids within the expanded bed through ports along the wall of the column. Component levels in the withdrawn streams can be assayed using on-line analytical chromatography or samples can be collected and assayed off-line. On-line monitoring can be used to control the duration of the loading stage and as a tool to provide information about the hydrodynamic and adsorption/desorption processes that occur during expanded bed adsorption. Studies of residence time distributions indicated that the modifications to the column do not significantly affect liquid dispersion. Using the adsorption of glucose-6-phosphate dehydrogenase from yeast homogenate on Streamline DEAE as a model system, comparison of breakthrough curves for runs when in-bed monitoring was and was not performed also suggested that separation efficiency is not appreciably affected by in-bed sampling.     

N-octane diffusivity enhancement via carbon dioxide in silica slit-shaped nanopores – a molecular dynamics simulation

Equilibrium molecular dynamics simulations were conducted to study the competitive adsorption and diffusion of mixtures containing n-octane and carbon dioxide confined in slit-shaped silica pores of width 1.9 nm. Atomic density profiles substantiate strong interactions between CO₂ molecules and the protonated pore walls. Non-monotonic change in n-octane self-diffusion coefficients as a function of CO₂ loading was observed. CO₂ preferential adsorption to the pore surface is likely to attenuate the surface adsorption of n-octane, lower the activation energy for n-octane diffusivity, and consequently enhance n-octane mobility at low CO₂ loading. This observation was confirmed by conducting test simulations for pure n-octane confined in narrower pores. At high CO₂ loading, n-octane diffusivity is hindered by molecular crowding. Thus, n-octane diffusivity displays a maximum. In contrast, within the concentration range considered here, the self-diffusion coefficient predicted for CO₂ exhibits a monotonic increase with loading, which is attributed to a combination of effects including the saturation of the adsorption capacity of the silica surface. Test simulations suggest that the results are strongly dependent on the pore morphology, and in particular on the presence of edges that can preferentially adsorb CO₂ molecules and therefore affect the distribution of these molecules equally on the pore surface, which appears to be required to provide the effective enhancement of n-octane diffusivity.     

大孔吸附树脂柱层析分离淫羊藿甙的研究

本文通过考察八种大孔吸附树脂对淫羊藿甙的吸附分离性能,筛选出了AB-8树脂作为分离纯化淫羊藿甙的介质。对该树脂的吸附性能研究表明其对浸提物中的淫羊藿甙有良好的吸附选择性,静态饱和吸附容量和动态吸附容量分别为22．97和16．20mg／mL。通过柱层析实验确定了AB-8树脂分离淫羊藿甙的工艺,经一步层析可将淫羊藿甙的纯度从2．78％提高到27％,回收率达97．3％。     

大孔吸附树脂对乳清分离蛋白酶解物的吸附特性研究

研究了大孔吸附树脂对乳清分离蛋白（WPI）酶解液的吸附特性。比较了6种大孔吸附树脂对WPI酶解物的静态吸附率与解吸附率。结果表明,DA201-C大孔吸附树脂最适合WPI酶解物的分离,其对WPI酶解液的动态吸附条件为：上样液浓度：10mg／mL;洗脱剂：75％乙醇溶液;洗脱剂流速：1BV／h。     

Adsorption/Desorption of toluene on clay minerals

Adsorption/desorption of toluene on montmorillonite, illite, and kaolinite was studied using the batch equilibrium method. The isotherms measured fit the Freundlich equation (r² >0.95). Montmorillonite adsorbed more toluene than illite or kaolinite; the adsorption of toluene on illite and kaolinite was not significantly different. Adsorption of toluene by montmorillonite showed an exponential increase as the ratio of toluene to clay was increased from 5 to 100. The rate studies showed that 62% of the adsorption was completed within 6 h. A rapid desorption was observed initially, followed by slow desorption after 1 h. The desorption rate decreased as the time of adsorption was increased. Almost all of the adsorbed toluene was extracted with water from the clay when the adsorption time was 0.1 h, but only 61% of the toluene could be desorbed when the adsorption time was 24 h.