蚓激酶白蛋白纳米粒的分离

目的分离除去蚓激酶白蛋白纳米粒溶液中未成粒的牛血清白蛋白 (BSA)。方法采用SephadexG 10 0凝胶柱分离纯化。结果流速为 1ml min时 ,短柱 (1.9cm× 11.5cm)、长柱 (1.9cm× 2 1.5cm)除去BSA的比例分别为 (16 .5± 5 .9) %、(18.2± 4 .0 ) % ;流速为 0 .3ml min时 ,短柱、长柱除去BSA的比例分别为 (18.6± 5 .1) %、(2 9.3±3.6 ) %。结论慢流速、长柱可以有效地除去BSA ,纯化蚓激酶白蛋白纳米粒     

硫鸟嘌呤白蛋白纳米粒的制备

目的用白蛋白包裹硫鸟嘌呤制成纳米粒,并通过纳米球的形态、载药量、包封率等考察纳米球的质量。方法以白蛋白纳米球为载体材料,硫鸟嘌呤为模型药物,采用乳化一交联固化法制备硫鸟嘌呤白蛋白纳米球。用扫描电镜观察纳米球的形态及其粒径,用紫外分光光度法测定纳米球的载药量和包封率。结果制得硫鸟嘌呤白蛋白纳米球外观呈米黄色,粉末状,球形圆整,粒径分布在189—205nm。载药量为7．31％,包封率为62．40％。结论硫鸟嘌呤白蛋白纳米球具有缓释作用。     

紫杉醇白蛋白纳米粒抗肿瘤临床研究进展

以白蛋白为载体的紫杉醇纳米粒在抗肿瘤方面发挥了重要作用。本文对紫杉醇白蛋白纳米粒体内药动学过程、纳米粒转运机制进行探讨,并就近几年来紫杉醇白蛋白纳米粒在乳腺癌、非小细胞肺癌及其他恶性肿瘤方面的临床研究作一综述,为临床应用提供借鉴。     

姜黄素白蛋白纳米粒的制备与评价

目的:优化姜黄素白蛋白纳米粒的处方工艺并对其特性进行表征。方法:以牛血清白蛋白为载体、通过反溶剂沉淀法制备载姜黄素纳米粒,以粒径为评价指标优选制剂处方及工艺,并考察所得纳米粒的放置稳定性、饱和溶解度及体外溶出度。结果:当有机相和水相体积之比为1∶20、药物与白蛋白用量之比为1∶1.5、保护剂为0.5%(V/V)甘露醇时,所得纳米粒冻干粉平均粒径约为320 nm。其在水、p H 6.8、p H 7.4 PBS中的溶解度显著高于原料药及物理共混物,体外溶出更快,且冻干粉的放置稳定性优于纳米混悬液。结论:白蛋白纳米粒处方能够改善姜黄素的水溶性及溶出度,放置稳定性较佳。     

表面活性剂对高水溶性药物阿魏酸钠白蛋白纳米粒的载药特性影响

目的:制备高水溶性药物白蛋白纳米粒,考察表面活性剂对高水溶性药物的包封作用。方法:以牛血清白蛋白为载体材料,阿魏酸钠为高水溶性药物模型,采用去溶剂化法制备阿魏酸钠白蛋白纳米粒。用低温超速离心法、层析-离心法、层析-酶解法对纳米粒包封率和载药量进行测定评价,并考察表面活性剂对纳米粒包封率、载药量及得率的影响。结果和结论:层析-离心法测定结果可靠。亲水性表面活性剂0.3%洛泊沙姆和亲脂性表面活性剂0·48%卵磷脂联合使用,有利于高水溶性药物的包封,包封率为28.42%,载药量为10.5%。     

靶向递药系统白蛋白纳米粒的研究进展

白蛋白纳米粒作为一种新型制剂,显示出独特的靶向肿瘤机制,且本身具有可生物降解、无毒、无抗原性、病人耐受等特点而表现出良好的应用前景。该文通过对白蛋白纳米粒国内外研究近期文献的归纳整理,较为系统的介绍了白蛋白纳米粒及其制备工艺、质量评价、药代动力学研究等。     

HPLC法测定苦参碱白蛋白纳米粒的包封率

建立苦参碱白蛋白纳米粒药物包封率测定的 HPLC 法。方法:采用离心超滤法分离苦参碱白蛋白纳米粒中的游离苦参碱,以 HPLC 为分析手段对纳米粒包封率进行测定评价。色谱条件:采用 Kromasil C_(18)柱(4.6 mm×150 mm,5μm);流动相:乙腈-0.02mol·L~(-1)磷酸二氢钾溶液(6:94);流速:1.0 mL·min~(-1);检测波长:210 nm;温度:25℃。结果:采用离心超滤法分离,HPLC 法测定,可达到游离苦参碱与纳米粒的有效分离,苦参碱峰与溶剂峰分离良好,苦参碱浓度在6～100μg·mL~(-1)范围内线性关系良好(r=0.9999),平均回收率在95.06%～100.9%之间,日内 RSD 和日间 RSD 均小于2%(n=5)。结论:本方法准确可靠,简单快速,可用于苦参碱白蛋白纳米粒药物包封率的测定。     

共载阿霉素和依克立达的PLGA纳米粒的制备及表征

目的 建立药物测定方法,并制备共载阿霉素和依克立达的PLGA纳米粒。方法 利用紫外分光光度法（UV）和高效液相色谱法（HPLC）分别建立阿霉素和依克立达的测定方法;采用纳米沉淀法制备共载纳米粒,通过调节两药的投药比,优化处方,考察纳米粒的粒径、形态、包封率、载药量以及体外释放。结果 阿霉素在1~40 μg/ml浓度范围内线性关系良好,标准曲线回归方程为A=0.021C+0.002,r=0.999 5; 依克立达在0.5~100 μg/ml浓度范围内线性关系良好,标准曲线回归方程为A=120 742.462 6C+1 974.570 4,r=1.000 0;通过处方优化,共载纳米粒的粒径约为50 nm,分布均一,呈圆形,阿霉素和依克立达的包封率分别为56.58%、51.66%,载药量分别为1.48%、1.85%,两药摩尔比约为1：1;体外释放缓慢。结论 分别建立了方便快捷、结果准确、重复性好的阿霉素和依克立达的检测方法,并且制备了分散性好、粒径较小的纳米粒,为后续实验提供基础。     

叶酸-白蛋白纳米粒偶联荧光素制备工艺的研究

目的研究叶酸-白蛋白纳米粒(叶酸-BSA纳米粒)偶联荧光素的制备工艺。方法制备叶酸-BSA纳米粒偶联物,将所得偶联物物理包合荧光素,通过透析将大部分未包裹的荧光素除去,并用葡聚糖凝胶柱色谱法进一步分离纯化,用紫外分光光度法测定荧光素上载效率。结果通过物理包合可以成功将荧光素包裹到叶酸-BSA纳米粒内,荧光素上载效率为6.4%。结论通过研究叶酸-BSA纳米粒包裹荧光素的制备工艺,可为进一步利用叶酸-BSA纳米粒偶联物包裹近红外荧光染料,对肿瘤体内在位监测奠定了基础。     

异甘草素固体脂质纳米粒包封率测定方法的研究

目的:建立异甘草素固体脂质纳米粒(ISO-SLN)包封率测定方法。方法:采用透析法分离样品中的游离药物及载药固体脂质纳米粒,并确定透析介质和透析时间;紫外分光光度法测定包封率,检测波长为396nm。结果:以2%泊洛沙姆188水溶液为透析介质、透析时间为8h,能有效分离ISO-SLN与游离ISO,加样回收率大于95%;ISO检测浓度线性范围为1.12～7.84μg·mL-1(r=0.9995),低、中、高浓度平均回收率为99.54%、99.11%、100.2%,RSD均小于5%;3批ISO-SLN平均包封率为80.2%。结论:所建立的方法可用于测定ISO-SLN包封率,且方法准确、简便。     

Toxicity of ZnO nanoparticles (NPs) with or without hydrophobic surface coating to THP-1 macrophages: interactions with BSA or oleate-BSA

It is recently shown that biological macromolecules in food could interact with nanoparticles (NPs) and consequently change the biological effects of NPs. In this study, the interactions between ZnO NPs with or without hydrophobic surface coating and bovine serum albumin (BSA) or oleate (OA) complexed to BSA (OA-BSA) were assessed. Atomic force microscope (AFM) showed topographic changes of both types of NPs by BSA or OA-BSA, which could indicate the formation of protein corona. ZnO NPs showed negative Zeta potential, which was slightly decreased by BSA or OA-BSA, with OA-BSA being more effective. The UV–Vis was increased, whereas the fluorescence and synchronous fluorescence was decreased by the presence of ZnO NPs. Exposure to both types of ZnO NPs was associated with cytotoxicity to THP-1 macrophages, which was equally mitigated by BSA or OA-BSA associated with decreased cellular Zn elements. Exposure to ZnO NPs was associated with decreased release of cytokines, which was not affected by BSA or OA-BSA. In combination, the results from this study suggested that both BSA and OA-BSA could be adsorbed to ZnO NPs regardless of hydrophobic surface coating, which reduced the cytotoxicity of NPs to macrophages probably due to reduced association between NPs and cells. BSA and OA-BSA equally protected THP-1 macrophages from ZnO NP exposure, which might indicate that complexation to OA did not compromise the cytoprotective effects of BSA. These data might also indicate the complex interaction between NPs and biological macromolecules as food components, which should be considered for future nanotoxicological studies.     

Influence of bovine serum albumin pre-incubation on toxicity and ER stress-apoptosis gene expression in THP-1 macrophages exposed to ZnO nanoparticles

When entering a biological environment, proteins could be adsorbed onto nanoparticles (NPs), which can potentially influence the toxicity of NPs. This study used bovine serum albumin (BSA) as the model for serum protein and investigated its interactions with three different types of ZnO NPs, coded as XFI06 (pristine NPs of 20?nm), NM110 (pristine NPs of 100?nm) and NM111 (hydrophobic NPs of 130?nm). Atomic force microscope indicated the adsorption of BSA to ZnO NPs, leading to the increase of NP diameters. Pre-incubation with BSA did not significantly affect hydrodynamic size but decreased Zeta potential of NM110 and NM111. The fluorescence and synchronous fluorescence of BSA were quenched after pre-incubation with ZnO NPs, and the quenching effects were more obvious for XFI06 and NM110. Exposure to all types of ZnO NPs significantly induced cytotoxicity and lysosomal destabilization, which was slightly alleviated when NPs were pre-incubated with BSA. However, ZnO NPs with or without pre-incubation of BSA resulted in comparable intracellular Zn ions, glutathione and reactive oxygen species in THP-1 macrophages. Exposure to ZnO NPs promoted the expression of endoplasmic reticulum (ER) stress markers (DDIT3 and XBP-1s) and apoptosis genes (CASP9 and CASP12). Pre-incubation with BSA had minimal impact on ER stress gene expression but decreased apoptosis gene expression. Combined, these results suggested that pre-incubation with BSA could modestly alleviate the cytotoxicity and reduce ER stress related apoptosis gene expression in THP-1 macrophages after ZnO NP exposure.     

Effect of molybdenum and copper on key enzymes of rat kidney with special reference to physiological antagonism

Enzymological data on alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, cholinesterase and lipase obtained in the kidney of rats, fed on molybdenum (Mo) and copper (Cu), are reported. Antagonistic or synergistic behaviour has been determined by feeding the rats simultaneously on these two metals. Molybdenum inhibited all other enzymes except acid phosphatase and lipase. Complete inhibition of alkaline phosphatase was recorded after copper treatment. The combined treatment with molybdenum and copper exhibited reversible enzyme changes, however, cholinesterase activity remained inhibited.     

Effects of Zn status,bile and other endogenous factors of jejunal Cd absorption

The possible contribution of endogenous factors to the control of intestinal Cd uptake was studied in rat jejunum isolated and perfused in situ. If Cd is trasported by the same mechanism as Zn, factors influencing Zn absorption should exert similar effects on that of Cd. In spite of an earlier demonstration of interaction between the 2 metals at the level of their intestinal absorption, the increased Zn uptake expected on the basis of previous observations on Zn-deficient rats is not accompoanied by increased Cd uptake. The mechanisms involved in Cd and Zn transport in the jejunum are therefore not identical. Cadmium, like Zn and Cu, is readily taken up from a perfusate free of exogenous ligands, so that there is no need to assume an obligatory role of such ligands in Cd absorption. Jejunal Cd transport was strongly depressed by secretions from the bile duct. This inhibition could not be accounted for by the protein content of the bile. On the other hand, micelle-forming bile salts completely abolished Cd absorption at or above a level corresponding to their critical micellar concentration. It is suggested that bile salts represent one endogenous factor which might be involved in preventing extensive Cd uptake from the intestinal lumen.     

The effect of albumin on the metabolism of ethoxyresorufin through O-deethylation and sulphate-conjugation using isolated rat hepatocytes

Ethoxyresorufin was metabolised by suspensions of isolated rat hepatocytes through O-deethylation to resorufin, followed by sulphate-conjugation of the resorufin. The deethylation but not the conjugation was greatly induced by 3-methylcholanthrene pretreatment in vivo. Induction altered the apparent deethylation V_max but not the apparent K_m value. With control hepatocytes there was a 3-fold difference between the apparent V_max values for deethylation (0.07) and conjugation (0.22 nmole/min/10⁶ hepatocytes) but none between the apparent K_m values (1.3 μM, deethylation and 1.0 μM, conjugation). After induction the deethylation V_max (10 nmole/min/10⁶ hepatocytes) was almost 13-fold higher than the conjugation V_max (0.81 nmole/min/10⁶ hepatocytes), but again there was no difference in the K_m values for the two reactions (2 μM). A significant proportion of the deethylation product, resorufin, passed out from the hepatocytes and then re-entered them in order to undergo conjugation. Extracellular bovine serum albumin inhibited the conjugation by binding resorufin that had left the hepatocytes. Albumin greatly increased the total resorufin formed from ethoxyresorufin, despite inhibiting very slightly the initial rate of deethylation.     

Transport of resveratrol, a cancer chemopreventive agent, to cellular targets: plasmatic protein binding and cell uptake

Resveratrol produced by several plants, berries and fruits, including grapes, is one of the best known natural food microcomponents with potent chemopreventive properties towards the most severe contemporary human diseases: cardiovascular sickness, cancer and neurodegenerative pathologies. Demonstration of its mechanism of action also implies the elucidation of the steps of bioavailability and bioabsorption in cells and tissues. In order to estimate the relationships between the amounts of resveratrol taken up by food or drink intake, and the several possible benefits illustrated from in vitro/in vivo experiments and from epidemiological studies, it is essential to demonstrate step by step the route of resveratrol from plasma to the cell active site. In plasma, resveratrol was shown to interact with lipoproteins. This commentary also contains previously unpublished results about interactions between resveratrol and albumin and the enhancement of this binding in presence of fatty acids. We have previously described that resveratrol uptake by hepatic cells involves two processes - a passive one and a carrier-mediated one. Thanks to this last process, resveratrol, while tightly bound to blood proteins, could be largely delivered to body tissues. The intracellular proteic targets of resveratrol remain to be identified.     

抗氧化活性藻蓝色素与牛血清白蛋白的相互作用

目的:进一步验证藻蓝色素(phycocyanobilin,PCB)的抗氧化作用,并研究藻蓝色素与牛血清白蛋白(bovine serum albu-min,BSA)之间的相互结合反应。方法:通过1,1-二苯基-2-苦基肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)清除法验证PCB的抗氧化作用。用荧光光谱法、分光光度法研究了PCB与BSA的相互结合反应。结果:PCB对DPPH自由基的清除作用呈现一定的量效关系。随着PCB浓度的增加,BSA的荧光强度有规律地降低且呈良好的线性关系。结论:抗氧化活性PCB能够有效地淬灭BSA的内源荧光,该猝灭作用属于静态荧光猝灭作用,反应的结合常数K=1.22×106L.mol-1,结合位点数n=1.14,与PCB的结合基本不会引起BSA的构象变化。     

荧光光谱法研究灯盏花素与牛血清白蛋白相互作用

目的 采用荧光光谱法研究灯盏花素与牛血清白蛋白(BSA)在生理条件下(pH 7.4)的相互作用机制。 方法 固定BSA浓度,依次加入不同浓度的灯盏花素溶液,在激发波长为280 nm下,290~500 nm的波长范围内进行荧光猝灭光谱、同步荧光光谱扫描。 结果 灯盏花素对BSA的荧光猝灭类型是静态猝灭;在温度288 K和310 K时,二者的结合常数KA分别为8.295×10⁵和3.302×10⁵ L·mol^-1;二者的结合位点数n分别为1.239 3和1.177 0。由热力学参数焓变(ΔH=-31.080 kJ·mol^-1)小于零和熵变(ΔS=5.392 J·mol^-1·K^-1)大于零,确定灯盏花素与BSA之间的作用力类型为静电作用力;生成自由能变(ΔG)为负值,表明灯盏花素与BSA的作用过程是一个自发过程。此外,应用同步荧光光谱考察了灯盏花素对BSA构象的影响。 结论 经过荧光光谱分析,可以确定灯盏花素与白蛋白的作用机制,为其开发成治疗心血管疾病新药提供理论依据。     

荧光光谱法研究葛根素与牛血清白蛋白的相互作用

目的:研究葛根素(puerarin,PR)与牛血清白蛋白(bovine serum albumin,BSA)的相互结合反应。方法:以 BSA 为荧光剂,PR 为荧光猝灭剂,在激发波长225 nm、发射波长340 nm 下测定荧光强度;分别测相同浓度的 BSA 和 PR 的荧光发射光谱和紫外吸收光谱。结果:随着 PR 浓度的增加,BSA 的荧光强度有规律地降低且呈良好的线性关系。结论:PR 与 BSA 的相互作用为静态猝灭过程。结合常数 K_R=1.37×10~6L·mol~(-1),供体(BSA)与受体(PR)间距离 r=3.44 nm,能量转移效率 E=0.670。根据热力学参数推测了 PR 与 BSA 的作用力类型。     

A standardised approach for the dispersion of titanium dioxide nanoparticles in biological media

Abstract

We describe a comprehensive optimisation study culminating in a standardised and validated approach for the preparation of titanium dioxide (TiO₂) nanoparticle dispersions in relevant biological media. This study utilises a TiO₂ reference nanomaterial based on a commercially available powder that has been widely examined in both acute and chronic toxicity studies. The dispersion approach as presented here satisfies four key harmonisation requirements not previously addressed: (1) method transferability, based in part on the use of a sonication energy calibration method that allows for power measurement and reporting in a device-independent manner; (2) optimisation of sonication parameters and thorough method validation in terms of particle size distribution, pH, isoelectric point, concentration range and batch variability; (3) minimisation of sonolysis side effects by elimination of organics during sonication and (4) characterisation of nanoparticle agglomeration under various dispersion conditions by use of laser diffraction spectrometry, an in situ size characterisation technique that provides advantages over other techniques more commonly employed within the context of nanotoxicology (e.g. dynamic light scattering). The described procedure yields monomodal, nanoscale, protein-stabilised nanoparticle dispersions in biological media that remain stable for at least 48 h (acute testing timeframe) under typical incubation conditions.