Kinetic study of Pt-cytostatics reactions by HPLC

HPLC with DAD (diode array detector) was applied as rapid method for the analytical control of the purity and stability of carboplatin and oxocarboplatin as effective cytostatics of 2nd generation. The stability of carboplatin has been measured in some infusion media (sodium chloride, glucose, sodium citrate) and compared to the cisplatin (cytostatic of 1st generation) stability. In addition ligand-exchange reactions between cisplatin and carboplatin have been studied together with the influence of temperature, pH and the concentrations of reactants. A method was developed for the analysis of clinical samples using solid-phase extraction as a preseparation and preconcentration step. The detection limits were 5 g/ml serum for cisplatin, 0.16 g/ml for carboplatin and 0.23 g/ml for oxo-carboplatin.Dedicated to Professor J. F. K. Huber on the occasion of his 65th birthday     

Protein Adsorption Switch Constructed by a Pillar[5]arene‐Based Host–Guest Interaction

The interfacial properties of solid substrates are of importance for protein adsorption. Herein, we report a reversible protein adsorption switch based on the host–guest interaction of the butoxy pillar[5]arene and adipic acid. By the detector of the contact angle (CA), atomic force microscopy (AFM), and luminoscope on the silicon substrate, the intelligent protein switch exhibits excellent adsorptivity for BSA and switch performance by pH regulation.     

Simultaneous monitoring of monoamines,amino acids,nucleotides and neuropeptides by liquid chromatography‐tandem mass spectrometry and its application to neurosecretion in bovine chromaffin cells

The primary functions of adrenal medullary chromaffin cells are the synthesis and storage in their chromaffin vesicles of the catecholamines noradrenaline (NA) and adrenaline (AD), and their subsequent release into the bloodstream by Ca²⁺‐dependent exocytosis under conditions of fear or stress (fight or flight response). Several monoamines, nucleotides and opiates, such as leucine‐enkephalin (LENK) and methionine‐enkephalin (MENK), are also co‐stored and co‐released with the catecholamines. However, other neurotransmitters have not been studied in depth. Here, we present a novel high‐resolution liquid chromatography‐tandem mass spectrometry approach for the simultaneous monitoring of 14 compounds stored and released in bovine chromaffin cells (BCCs). We validated the analytical method according to the recommendations of the EMA and FDA by testing matrix effect, selectivity, sensitivity, precision, accuracy, stability and carry‐over. After testing on six batches of BCCs from different cultures, the method enabled simultaneous quantitative determination of monoamines (AD, NA, dopamine, serotonin, 5‐hydroxyindoleacetic acid, histamine and metanephrine), amino acids (L‐glutamic acid, γ‐aminobutyric acid), nucleotides (adenosine 5′‐diphosphate, adenosine 5′‐monophosphate, cyclic adenosine 5′‐monophosphate) and neuropeptides (LENK and MENK) in the intracellular content, basal secretion and acetylcholine induced secretion of BBCs. The high‐resolution approach used here enabled us to determine the levels of 14 compounds in the same BCC batch in only 16 min. This novel approach will make it possible to study the regulatory mechanisms of Ca²⁺ signaling, exocytosis and endocytosis using different neurotrophic factors and/or secretagogues as stimuli in primary BCC cultures. Our method is actually being applied to human plasma samples of different therapeutic areas where sympathoadrenal axis is involved in stress situations such as Alzheimer's disease, migraine or cirrhosis, to improve diagnosis and clinical practice. Copyright © 2016 John Wiley & Sons, Ltd.     

Reduced Graphene Oxide Non‐covalent Functionalized with Zinc Tetra Phenyl Porphyrin Nanocomposite for Electrochemical Detection of Dopamine in Human Serum and Rat Brain Samples

We described the use of a nanocomposite consisting of reduced graphene oxide and zinc tetraphenylporphyrin (RGO/Zn‐TPP) for electrochemical sensing of dopamine (DA). The surface of RGO was homogeneously functionalized with Zn‐TPP via non‐covalent π‐π interaction. The nanocomposite was characterized by scanning electron microscopy, UV‐Vis spectrometry, nuclear magnetic resonance spectroscopy and electrochemical impedance spectroscopy. The electroanalysis behavior of the nanocomposite was studied by cyclic voltammetry and amperometry. The excellent electrocatalytic activity is found for oxidation of DA, best at working voltage of 0.214 V (vs. Ag/AgCl) and linear response range of 0.04–238.8 μM. The sensitivity and detection limit were of 0.665 μA µM^?1 cm^?2 and 3 nM, respectrively. The electrode is well reproducible, stable, and represents a viable platform for the analysis of DA in DA injection, human serum and rat brain sample.     

中药成分七叶内酯-BSA-金属离子的相互作用

以荧光光谱、紫外光谱技术研究了传统中药(秦皮)有效成分七叶内酯与BSA在金属离子Cu2 、Ni2 、Zn2 和Co2 分别共存时的相互作用。发现七叶内酯与BSA的表观结合常数KA、七叶内酯对BSA内源荧光的猝灭常数KP增大,按KA和KP数值改变程度,四种金属离子的排序与Irving-William s稳定性序列部分相符:Co2 >Cu2 >N i2 >Zn2 ,但结合位点数n、结合空间距离r和分子间作用力类型基本未变。推测金属离子可能在七叶内酯与BSA之间以“离子架桥”方式直接参与七叶内酯-BSA的结合过程。     

二乙基巴比妥酸与牛血清白蛋白相互作用的荧光光谱法

二乙基巴比妥酸;牛血清白蛋白;荧光光谱法;热力学参数     

二氧化钛催化超声波损伤牛血清白蛋白的研究

利用紫外可见(UV-Vis)光谱和荧光(FL)光谱研究了二氧化钛(TiO₂)催化超声波照射对牛血清白蛋白(BSA)的损伤作用，同时对金红石型和锐钛矿型TiO₂的催化性能进行了比较，并探讨了照射时间，TiO₂加入量，溶液酸度，超声波功率和离子强度等因素对BSA分子损伤的影响。结果表明，金红石型TiO₂的催化效果明显好于锐钛矿型TiO₂。在一定条件下，BSA分子的损伤程度随着照射时间的延长、照射功率和溶液酸度的增大而增大，而TiO₂的加入量和离子强度对BSA分子损伤的影响则较为复杂。     

毛细管电泳研究抗癌药物紫杉醇与人血清蛋白结合作用

采用毛细管区带电泳(CZE)技术, 研究了天然抗癌药物紫杉醇(Paclita-xel)与人血清白蛋白(HSA)的结合机制. 在以硼砂-碳酸钠(pH 10, 50 mmoL)为运行缓冲溶液, 运行电压21 kV, 进样时间5.0 s, 紫外检测器(214 nm)的条件下检测, 结合常数和结合位点数在298和310 K分别为K298 K=1.7×104 L/mol, n298 K=4.1, K310 K=3.4×104 L/mol, n310 K=3.0.     

牛血清白蛋白修饰毛细管整体柱的制备及组氨酸对映体分离

以甲基丙烯酸缩水甘油酯为单体, 乙二醇二甲基丙烯酸酯为交联剂, 环己醇和正十二醇混合溶液为致孔剂, 在最佳聚合条件下, 以偶氮二异丁腈为引发剂, 制备了毛细管整体柱基质, 并且研究了单体、交联剂及致孔剂对整体柱基质孔结构及渗透性的影响; 使用Epoxy方法在基质表面键合BSA, 制得BSA修饰的毛细管整体柱. 将此毛细管整体柱应用于毛细管电色谱中, 成功地分离出了组氨酸对映体, 分离度良好.     

共振散射光谱法研究人血清白蛋白与二甲酚橙的反应

对二甲酚橙作为光散射探针测定蛋白质进行了研究,基于人血清白蛋白对二甲酚橙的共振光散射强度的增强效应,建立了测定蛋白质的共振散射光谱法。在pH 4.00的NaOAc-HOAc缓冲溶液中,二甲酚橙只有微弱的光散射强度,但它与蛋白质的缔合物却有较强的共振光散射信号,在λ=517 nm处,光散射强度达到最大,并且与蛋白质浓度在为0.0~10.0 mg.L-1范围呈线性,检出限为0.044 mg.L-1。运用摩尔比法测定二甲酚橙和蛋白质的结合数为132,用于实际样品的分析,测定值与考马斯亮蓝法的结果一致,分析结果的RSD值(n=5)均小于5%。