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61.
Seo Woo Song Hyung Jong Bae Sudeok Kim Dong Yoon Oh Okju Kim Yunjin Jeong Sunghoon Kwon 《Particle & Particle Systems Characterization》2017,34(5)
Microparticle‐based drug delivery is a promising technology for small volume bioassay platforms. The general utilization of the drug‐loaded microparticles in the in vitro bioassay platforms requires the drug loading method, which should impregnate the general drug types (e.g., water insoluble) with high payload into the variously designed microparticles. Loading the drug into the prefabricated microparticles using solvent evaporation satisfies the requirement. However, similar to the “coffee‐ring effect,” drugs are loaded in a seriously nonuniform manner, caused by the capillary flow during the evaporation process. Here, it is presented that the freeze‐drying is an efficient way to load uniform and high amount of the drug into the prefabricated microparticles. It is demonstrated that freezing solvent can block the capillary flow during the solvent removal process, improving the loading uniformity. The delivered amount of drugs is linearly proportional to the initial loading amount of drugs. Also, this drug loading method is shown to be applied to the various drug types and the prefabricated microparticles with different properties. Considering many challenges to suppress the “coffee‐ring effect” that induces nonuniform impregnation/deposition, the proposed concept can be applied not only for microparticle‐based drug delivery but also for uniform coating applications (e.g., thin‐film coating, DNA/protein microarray). 相似文献
62.
用同步荧光光谱法评估原发性肝细胞癌患者血浆、肝癌荷瘤小鼠以及培养细胞(HepG2和HL-7702)中酪氨酸(Tyr)和色氨酸(Trp)残基水平变化。固定发射波长λem和激发波长λex之间的波长差Δλ分别为20和60 nm,激发和发射单色器同时进行扫描,确定350 nm为Trp的同步特征发射峰位置,318 nm为Tyr的同步特征发射峰位置。结果表明,肝癌患者及荷瘤小鼠血浆蛋白质所含Tyr和Trp残基的荧光强度明显增加。相反,肝癌细胞或荷瘤小鼠肿瘤组织中Tyr和Trp残基荧光强度却随生长时间增长而减少。进一步实验表明,具有抗癌活性的苦参碱处理癌细胞后,细胞Tyr和Trp残基的荧光强度升高。这些结果表明,Tyr和Trp残基的变化可能参与了肿瘤的发生发展。 相似文献
63.
ABSTRACT The interaction between phenformin hydrochloride and bovine serum albumin (BSA) was investigated by the methods of chemiluminescence combined with equilibrium dialysis technique. A novel N-bromosuccinimide (NBS)–eosin Y (EY) chemiluminescence (CL) method was established for the determination of phenformin. The mechanism of this chemiluminescence system was proposed. Optimization studies were performed to determine the phenformin. Under the optimal conditions, the CL intensity was linear for a phenformin concentration over the range of 4.6 × 10?8 to 5.0 × 10?5 g/mL. The detection limit was 1.5 × 10?8 g/mL. The data obtained by the present equilibrium dialysis–CL system were analyzed using the Klotz plot and the Scatchard analysis. The results showed that the Klotz plot and the Scatchard plot are linear with good correlation coefficient, indicating that the phenformin has only one type of binding site on BSA. The binding parameters were the number of the binding sites n (1.02) and the estimated association constant K (2.66 × 104 L/mol). The chemiluminescence system combined with equilibrium dialysis developed in this work demonstrated its use for determination of interaction between drug and protein by using relatively simple instrument. 相似文献
64.
文章作者用磁镊与原子力显微镜研究了抗癌药物顺铂对单个DNA分子结构的影响.当顺铂浓度较低时,DNA链变得柔软,驻留长度从~52 nm显著缩短到~15 nm;当顺铂浓度较高时,DNA表现出凝聚现象.基于单分子拉伸和原子力显微镜(AFM)成像两方面的实验结果,文章作者提出一个顺铂导致的DNA变软(softening)-成环(looping)-缩短(shortening)-凝聚(condensing)模型(简写为SLSC模型)来解释观察到的DNA凝聚,并认为通过远程交联使DNA形成小环结构是铂类抗癌药物作用的重要特征. 相似文献
65.
本文测定了新疆产新疆党参,新疆元胡等12种中草药中十种微量金属元素的含量.结果表明这些中草药中具有显著生理活性的Zn、Fe、Cu、Mn等元素.它们的含量除了个别样品外均大于或接近于国内其它地区所产的同种中草药、根据冠心病病因的Zn/Cu值假说和微量金属元素的含量关系,新疆产12种中草药也可用于防治冠心病. 相似文献
66.
A sonochemical based green synthesis method playa powerful role in nanomaterials and composite development. In this work, we developed a perovskite type of strontium titanate via sonochemical process. SrTiO3 particles were incorporated with nitrogen doped graphene oxide through simple ultrasonic irradiation method. The SrTiO3/NGO was characterized by various analytical methods. The nanocomposite of SrTiO3/NGO was modified with laser-induced graphene electrode (LIGE). The SrTiO3/NGO/LIGE was applied for electrochemical sensor towards chemotherapeutic drug detection (nilutamide). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques have been used to examine the electrochemical performance of nilutamide (anti-cancer drug). DPV was found to be more sensitive and found to exhibit a sensitivity 8.627 µA µM−1 cm−2 for SrTiO3/NGO/LIGE with a wide linear range (0.02–892 µM) and low Limit of detection (LOD: 1.16 µM). SrTiO3/NGO/LIGE has been examined for the detection of nilutamide in blood serum and urine samples and obtained a good recovery in the range of 97.2–99.72 %. The enhanced stability and selectivity and practical application results indicates the suitability of SrTiO3/NGO/LIGE towards the detection of nilutamide drug in pharmaceutical industries. 相似文献
67.
留数定理是高校物理专业必修课程数学物理方法中的一个重要定理.传统教学中关于该定理的讲授着重于数学公式的推导和数学思想的传达,而对于其在具体物理问题上的应用鲜有涉及.本文以一维Su-Schrieffer-Heeger模型的拓扑相变问题为例,阐明了如何利用留数定理解析得到二阶位移量的表达式并用该物理量表征拓扑相变.在讲授留数定理的教学过程中引入具体物理问题的分析实例,可以使学生更深刻地理解数学定理中的物理内涵. 相似文献
68.
合成乳酸乙酯精馏残液的分析张青枝,华国雄,鲁富贵,张深松,赵根锁(河南师范大学化学系新乡453002)(河南省化学研究所郑州)关键词乳酸乙酯,精馏残液,红外光谱,电子轰击质谱采用乳酸、乙醇直接酯化法[1],有机溶剂共沸法[2],合成乳酸乙酯收率较低。... 相似文献
69.
70.
气相色谱法测定茶叶及土壤中的高效氯氟氰菊酯残留量 总被引:4,自引:0,他引:4
建立了气相色谱测定茶叶及土壤中高效氯氟氰菊酯残留量的分析方法。茶叶和土壤样品用正己烷提取,毛细管柱分离,气相色谱-电子捕获检测器(GC-ECD)检测。结果表明: 在高效氯氟氰菊酯添加量为0.02~2.00 mg/kg范围内,高效氯氟氰菊酯在鲜茶叶和土壤中的平均添加回收率分别为89.0%~94.1%和89.8%~94.7%,相对标准偏差(RSD, n=5)分别为3.0%~4.9%和2.5%~4.2%,方法的最低检出限(S/N=3)为0.002 mg/kg。采用该方法测定2.5%高效氯氟氰菊酯微乳剂在湖南长沙茶叶及土壤中的消解动态,其符合一级动力学消解模式,消解方程分别为y=3.1996e-0.3394x和y=0.1224e-0.1036x,相关系数分别为0.9956和0.9247。在茶叶中的半衰期为2.04 d,在土壤中的半衰期为6.69 d。该方法为湖南长沙地区茶叶种植科学合理地使用杀虫剂高效氯氟氰菊酯提供了依据。 相似文献