Study on the Interaction Between Bovine Serum Albumin and Potassium Perfluoro Octane Sulfonate

The interactions between potassium perfluorooctanesulfonate (PFOS) and bovine serum albumin (BSA) were studied by fluorescence spectroscopy. The association constants between PFOS and BSA were obtained by fluorescence enhancing and fluorescence quenching respectively. Furthermore, fluorescence quenching was studied at different temperatures, and the binding constant was also determined by the method of fluorescence quenching. According to the thermodynamic parameters, the main binding force could be judged. The experimental results revealed that BSA and PFOS had strong interactions. The mechanism of quenching belonged to dynamic quenching and the main sort of binding force was hydrophobic force. IR-spectra proved the interaction changed the conformation of BSA.     

Reversal of elution order of N‐(2,4‐dinitrophenyl)‐proline and N‐(2,4‐dinitrophenyl)‐serine in HPLC by BSA chiral stationary phase

N‐(2,4‐dinitrophenyl)‐proline and N‐(2,4‐dinitrophenyl)‐serine were enantiomerically resolved on the BSA chiral stationary phase by HPLC in reversed‐phase mode. Effects of chromatographic conditions on enantioseparation and elution order have been investigated in detail. For these two samples, reversal of enantiomer elution order was observed by changing buffer pH, the content of acetonitrile, or alcohol modifiers in mobile phase, which is firstly reported in the BSA chiral stationary phase studies. More interestingly, combined effect between buffer pH and the content of acetonitrile was also observed. In addition, coelution range of enantiomers varied along with the content of acetonitrile in mobile phase.     

Effect of Polyethylene glycol methyl ether blend Humic acid on poly (vinylidene fluoride-co-hexafluropropylene) PVDF-HFP membranes: pH responsiveness and antifouling behavior with optimization approach

Flat sheet asymmetric membranes were fabricated with homogeneous solution of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) using N-methyl-2-pyrrolidone (NMP) as solvent via phase inversion method. PEGME (Poly ethylene glycol methyl ether) (M_n 5000) blend Humic Acid (HA), of different mole ratio was used as additive. Characterization of the membranes was done by Field emission scanning electron microscope (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, Atomic force microscopy (AFM) and Differential scanning calorimetry (DSC) studies. Liquid-liquid displacement porosimetry (LLDP) study evaluated the morphological parameters, average pore size and pore size distribution. Bovine serum albumin (BSA) (M_W - 68,000 Da) was used to study the antifouling effect and pore blocking mechanism of the membranes. The pure water flux (PWF), solute rejection and flux recovery ratio drastically increases for the PEGME blended HA membranes whereas the water contact angle decreases significantly. The pH responsiveness character of the prepared membranes altered the hydraulic permeability and rejection % at different pH. Finally, optimization of the variables contributing towards the PWF and BSA rejection of the desired membrane was performed using Design expert software 9.0 TRIAL through ANOVA (analysis of variance) using the combination of response surface methodology (RSM) and central composite design (CCD).     

线性扫描伏安法研究大豆甙元与牛血清白蛋白的相互作用

采用线性扫描伏安法研究了大豆甙元与牛血清白蛋白(BSA)之间的相互作用;探讨了缓冲体系、pH、反应时间、反应温度、扫描速率等对相互作用的影响.结果表明,在pH为7.4的B-R缓冲溶液中,大豆甙元与BSA在相互作用20min后形成1∶1型的单一的非电活性超分子化合物,两者的结合常数β=8.29×105 L·mol-1,转移系数α=0.367 9,表观电子传递速率常数ks为1.39s-1.     

Characterization of Chitosan/Alginate Self-Assembled Nanoparticles as a Protein Carrier

The aim of this study was to evaluate the effect of the polymeric ratios on the characteristics of chitosan/alginate (ch/alg) self-assembled nanoparticles and their potential as protein delivery vehicle. The nanoparticles were prepared using proper mixing of polymers in presence or absence of bovine serum albumin (BSA) as a protein model. Three formulations of nanoparticles comprising ch/alg ratios of 2:1, 1:1, and 1:2 were prepared. Size, shape and zeta potential of the formulations were studied by scanning electron microscopy (SEM) and nanosizer instruments. FTIR, and differential scanning calorimetery (DSC) studies were performed to investigate polymer-polymer or polymer-protein interactions. Release profiles and entrapment efficiencies of the nanoparticles were determined by calorimetric technique using appropriate techniques. Entrapment efficiency was 70% for ch/alg ratio of 1:1, 65% for 1:2, and 60% for 2:1. The z-average size of the nanoparticles were 403, 205, and 318 nm for ch/alg ratios of 2:1, 1:1, and 1:2, respectively. Average zeta potentials were ?47, +15, ?25 mV for 2:1, 1:1, and 1:2 as well. Considering the favorable features required for protein delivery systems, ch/alg (1:1) due to its smallest size, highest loading, and most homogenous shape was regarded as the best ratio.     

镍(Ⅱ)、镉(Ⅱ)与去甲基斑蝥酸钠和咪唑配合物的结构、与DNA/BSA的作用及抗增殖活性

以2种配体去甲基斑蝥酸钠(Na₂DCA=7-氧杂二环[2.2.1]庚烷-2,3-二甲酸钠)和咪唑(IM),分别与镍(Ⅱ)和镉(Ⅱ)的醋酸盐通过溶液法合成了2种配合物[Ni(IM)(DCA)(H₂O)₂]·2H₂O(1),[Cd₂(IM)₄(DCA)₂]·2H₂O(2)。应用元素分析、热重分析、红外光谱及X-射线单晶衍射法对配合物的组成和结构进行了表征。配合物1与2的中心离子分别与咪唑的亚胺氮原子、去甲基斑蝥酸根的羧基氧原子和醚键氧原子配位,配位数均为6,分别为单核(1)和双核(2)配合物。通过紫外光谱法、荧光光谱法和粘度法研究了配合物与DNA的相互作用。结果表明,配合物能通过部分插入模式与DNA发生较强的结合作用(K_b:5.51×10³(1)、1.01×10³(2)L·mol^-1)。同时,利用荧光光谱法研究了配合物与牛血清白蛋白(BSA)的相互作用。配合物能与BSA发生强烈的相互作用(K_AM:1.91×10⁵(1)和6.17×10⁵(2)L·mol^-1),结合位点数均为1。测试了配合物对人肝癌细胞(SMMC₇₇₂₁)和人乳腺癌(MCF-7)的体外抗增殖活性。结果显示,配合物对不同癌细胞具有选择性抑制作用。镍配合物(1)对SMMC₇₇₂₁的抗癌活性较去甲基斑蝥酸钠有明显提高。     

Preparation and characterization of a polystyrene/bovine serum albumin nanoparticle‐coated capillary for chiral separation using open‐tubular capillary electrochromatography

Polystyrene (PS) nanoparticles coated by BSA, hereafter denoted as PS/BSA, were prepared and chemically immobilized for the first time onto a capillary inner wall for open‐tubular CEC (OTCEC). EOF and scanning electron micrography were used to characterize the prepared nanoparticle‐coated capillaries. To investigate the performance of the prepared columns in OTCEC, chiral separation of d ,l ‐tryptophan (dl ‐Trp) was performed in monolayer BSA‐modified capillary and PS/BSA nanoparticle‐coated columns. The results indicated that the nanoparticle‐modified column afforded a higher resolution compared with the monolayer type. Rapid enantioseparation of dl ‐Trp (within 3 min) was achieved with the PS/BSA‐immobilized column using an electroosmotic pump‐assisted CEC. Enantiomer separations of other compounds like dl ‐tyrosine and warfarin were also achieved with the column. Besides, run‐to‐run and column‐to‐column repeatabilities of the PS/BSA‐coated column in the chiral separation were systematically introduced.     

Mannose‐BSA Conjugates: Comparison Between Commercially Available Linkers in Reactivity and Bioactivity

Mannosyl ethanolamine and BSA were conjugated together by their amino groups with various homobifunctional cross‐linker reagents: disuccinimidyl carbonate (DSC), disuccinimidyl glutarate (DSG), disuccinimidyl suberate (DSS), ethylene glycolbis(succinimidylsuccinate) (EGS), 1,5‐difluoro‐2,4‐dinitrobenzene (DFDNB), diethyl squarate (DES), and thiophosgene (TP). The resulting mannose-BSA conjugates were subjected to an enzyme‐linked lectin assay (ELLA)to investigate their affinity to concanvalin A (ConA). With these results, the seven linkers were evaluated on the basis of five criteria, i.e., cost, reactivity, sugar loading, homogeneity, and affinity to ConA. Thus, DSS, DFDNB, and DES seemed to have advantages over the other cross-linking reagents.     

3-羟基-6-[(4-羧基苯基)偶氮]-苯甲酸与牛血清蛋白结合反应的荧光光谱

采用荧光光谱研究3-羟基-6-[(4-羧基苯基)偶氮]-苯甲酸(HCPAB)与牛血清蛋白(BSA)的相互作用.通过测定298K和310K下HCPAB与BSA的荧光猝灭光谱,计算得到荧光猝灭常数、反应的结合常数、结合位点数及热力学参数,得出这种荧光猝灭机理符合静态猝灭;由Foerster能量转移机理,计算了当BSA与HCPAB比例为1∶1时分子间距离r=3.18nm和能量转移效率E=0.23,并由同步荧光光谱显示HCPAB与BSA的结合位点更接近于色氨酸.     

诺氟沙星-Tb3+-牛血清白蛋白相互作用的荧光光谱研究

采用诺氟沙星-Tb3 体系,在pH 9.0的Tris-HCl缓冲溶液中,利用牛血清白蛋白(BSA)能增强诺氟沙星的特征荧光的特性,建立了BSA的定量分析方法。结果表明:当诺氟沙星浓度/[Tb3 ]在1/8~1/12范围内时,BSA的加入量与体系的荧光增强(ΔF)有良好的线性关系,线性范围为0~25μg/mL,相关系数r=0.998。并初步探讨了BSA的存在对诺氟沙星-Tb3 体系荧光增强的作用机理。