壳聚糖修饰的银纳米粒子对色氨酸的紫外检测

基于银纳米粒子的传感器的应用引起了广泛关注,原因是其具有简便、高效和经济的特点。我们在水相中合成了壳聚糖修饰的银纳米粒子,通过紫外检测,实现了对色氨酸的选择识别,并初步探讨了它们作用的可能机制。     

磷酸化聚乙烯醇修饰磁性纳米粒子对铀酰的吸附性能研究

在Fe3O4磁性纳米粒子表面复盖一层磷酸化聚乙烯醇制备了一种用于从水相选择性分离铀酰的复合型磁性纳米粒子。用平衡吸附法研究了纳米粒子对铀酰的吸附性能和选择识别能力,且探讨了实验条件对纳米粒子吸附性能的影响。结果表明在竞争金属离子存在下,纳米粒子对铀酰具有较高的吸附能力和选择识别能力,且可以循环使用。     

牛血清白蛋白在交联壳聚糖微球上的吸附研究

采用反相悬浮法,以甲醛为预交联剂,环氧氯丙烷交联制备壳聚糖微球,用红外光谱和扫描电镜对微球进行表征,并用于牛血清白蛋白的吸附研究.考察了吸附时间、溶液pH值、牛血清白蛋白的浓度、温度、氯化钠含量等因素对牛血清白蛋白吸附的影响.结果表明,交联CTS微球不溶于酸和碱,对牛血清白蛋白具有良好的吸附性能,在pH 5.0时,吸附在1.5 h内可达平衡,吸附数据符合Langmuir等温方程.     

纳米钛酸锶钡对牛血清白蛋白的吸附行为

以硝酸钡、硝酸锶和钛酸四正丁酯为原料,采用柠檬酸络合溶胶-凝胶法制备纳米钛酸锶钡(nano-barium-strontium titanate,n-BST)粉体。用X射线衍射、透射电子显微镜和Fourier变换红外分析表征n-BST粉体的结构与性能。研究n-BST粉体对牛血清白蛋白(bovine serum albumin,BSA)的吸附行为,考察吸附条件和洗脱条件,并分别用红外光谱和紫外光谱以及荧光光谱分析吸附作用和解吸过程对BSA结构的影响。结果表明:当介质的pH=4.10时,n-BST对BSA具有很强的吸附能力,其吸附行为符合Langmuir吸附等温方程式和HO准二级动力学模型,吸附过程的焓变ΔH=-13.30kJ/mol,自由能变(ΔG)和熵变(ΔS)均为负值,吸附活化能Ea=16.18kJ/mol,该吸附过程是以氢键作用力为主的自发放热过程。被吸附的BSA可用pH=7.54的缓冲溶液完全洗脱。吸附过程和洗脱过程没有明显改变BSA的结构。     

BSA修饰Fe_3O_4纳米颗粒用于苦瓜提取液中活性成分的筛选

用一步法直接合成了表面氨基化修饰的Fe3O4纳米颗粒(NH2-MION),通过双功能团试剂戊二醛将牛血清白蛋白(BSA)固定在NH2-MION表面,将BSA-MION用于苦瓜提取液中活性成分的筛选,利用气相色谱-质谱联用技术鉴定出了3种与BSA作用较强的活性成分。     

壳聚糖纳米粒子改性反渗透膜的制备及性能研究

采用反相乳化法制备了壳聚糖纳米粒子(CSNP),以聚醚砜超滤膜为基膜,将CSNP添加在水相中通过界面聚合方法制备了一系列薄层纳米复合(TFN)反渗透膜,研究了CSNP添加量对TFN膜性能的影响。结果表明,CSNP优化添加质量分数为0.010%,即TFN-10膜对NaCl的截留率达到98.89%,水通量为40.53 L/(m~2·h),远高于TFN-0(TFC)膜的水通量(22.92 L/(m~2·h));且TFN-10膜在48 h的长期运行后,水通量和截留率分别稳定在32.20 L/(m~2·h)和99.07%,稳定性良好;对HA抗污染测试中,通量恢复率为83.67%,总污染率为24.84%,抗污染性能明显优于TFC膜(通量恢复率44.88%,总污染率58.19%)。     

羧甲基化壳聚糖修饰磁性Fe_3O_4纳米粒子去除Cu（Ⅱ）离子

采用化学共沉淀法制备磁性Fe₃O₄纳米粒子,通过在磁性Fe₃O₄纳米粒子表面接枝高脱乙酰度羧甲基化壳聚糖（CMC）,制备了一种新型磁性纳米吸附剂。通过透射电镜、红外光谱、X射线衍射、振动样品磁强计对其进行了表征,着重研究其对Cu(Ⅱ)离子的吸附性能。结果表明：溶液pH值能显著影响吸附剂对Cu(Ⅱ)的吸附效果,pH值为5时其效果最佳。等温吸附数据符合Langmuir 模型,T＝298 K、pH＝5、V＝5 mL时,吸附剂的饱和吸附容量q_m高达71.43 mg/g,吸附常数为0.0543 L/mg。     

水溶性壳聚糖纳米粒子的制备及其BSA载药性能

为了避免高分子量壳聚糖水溶性差以及增溶剂乙酸可能带来的负面作用,本文选择低分子量水溶性壳聚糖 (WSC)作研究对象,采用三聚磷酸(TPP)作交链剂制备不同WSC/TPP比率的WSC纳米粒子,并用于牛血清白蛋白 (BSA)的释放载体。经测得为球形形貌的纳米粒子空载和载药时粒径、Zeta电位分别在35～190 nm、35～42 mV。红外光谱及X–射线衍射证实了纳米粒子中WSC的氨基与TPP的磷酸基团发生了交联反应。纳米粒子载药性能试验表明在0.05～1 mg/mL范围内随着BSA浓度的增大,纳米粒子的载药量增加而负载率降低。体外释放实验表明水溶性壳聚糖纳米载体对蛋白质药物具有缓释特征。因此,水溶性壳聚糖有望成为新的载体应用于蛋白质药物的控制释放。     

复合磁性壳聚糖微球对BSA的吸附机理研究

将脱乙酰度为85%的壳聚糖包裹在由二价和三价的铁离子共沉淀制得的Fe3O4磁子表面,用环氧氯丙烷作为交联剂进行交联制成磁性壳聚糖(简称MC),用于吸附蛋白质一磷酸氢二钠一柠檬酸缓冲溶液中的小牛白蛋白(BSA),利用TEM(透射电镜)、IR(红外光谱)、TG-DSC(失重-差热)、XRD(粉末衍射)分析微球的形貌、组成及热件能,考察了牛白蛋白的初始浓度、溶液pH及保温时间对蛋白质吸附程度的影响.结果显示,pH增大使蛋白质的吸附量减小;在一定范围内,增大蛋白质的初始浓度和延长保温时间均有利于增加蛋白质的吸附量,温度对微球吸附蛋白质的影响比较复杂.     

磁性纳米粒子/污泥基复合材料吸附性能研究进展

随着城市污水处理厂数量和规模的不断发展,污泥的处理与资源化利用成为环保领域的热点问题。制备磁性纳米粒子/污泥基复合材料处理水环境中的污染物是污泥资源化研究的重要方向之一,可达到污泥资源化利用及环境修复的双重目的。综述了磁性纳米粒子/污泥基复合材料的制备方法、吸附实验研究方法、吸附影响因素及吸附机理,并对磁性纳米粒子/污泥基复合材料的发展前景及研究方向进行了展望。     

Preparation and release behavior of carboxymethylated chitosan/alginate microspheres encapsulating bovine serum albumin

Microspheres were prepared from carboxymethylated chitosan (CM‐chitosan) and alginate by emulsion phase separation. Their structure and morphology were characterized with IR spectroscopy and scanning electron microscopy. Bovine serum albumin (BSA) was encapsulated in the microspheres to test the release behavior. The swelling behavior, encapsulation efficiency, and release behavior of BSA from the microspheres at different pHs and with a pH‐gradient condition were investigated. The BSA encapsulation efficiency was calculated to be 80%. The degree of swelling of the microspheres without BSA loaded at pH 7.2 was much higher than that at pH 1.0. The encapsulated BSA was quickly released in a Tris–HCl buffer (pH 7.2), whereas a small amount of BSA was released under acid conditions (pH 1.0) because of the strong electrostatic interaction between ? NH₂ groups of CM‐chitosan and ? COOH groups of alginic acid and a dense structure caused by a Ca²⁺ crosslinked bridge. For the simulation of the processing of the drug under the conditions of the intestine, the microspheres were tested in a pH‐gradient medium, in which an acceleration of the release occurred at pH 7.4 after a lag time at a low pH (5.8–6.8). At pH 7.4, a large amount of BSA was released from the microspheres in a short time because of the rapid swelling of the microspheres. However, the release only depended on the diffusion of BSA at relatively low pHs, this resulted in a relatively low release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 878–882, 2004     

Wettability and surface free energy of bovine serum albumin films

Measurements of the contact angle for water, glycerol, formamide, ethylene glycol, and diiodomethane on polymethyl methacrylate covered by adsorptive bovine serum albumin (BSA) films were made. Adsorption was performed from solutions in the concentration range 0–100 g/L. From the obtained contact angles the Lifshitz-van der Waals components and the values of the electron-acceptor and electrondonor parameters of the acid-based components of the films were calculated for six triplets of liquids. The biggest changes in the BSA film structure occurred under a monolayer coverage (i.e., at BSA concentrations of <2.5 g/L). On the basis of the contact angles of glycerol, ethylene glycol, and formamide it was concluded that the density of BSA polar groups was almost constant. The surface density of the hydrophobic part of the BSA film also seemed constant regardless of the concentration of the solution from which the BSA adsorptive film was created. This conclusion could be drawn from the almost constant contact angle of diiodomethane.     

药根碱与牛血清白蛋白相互作用的光谱研究

采用荧光和UV光谱法研究了盐酸药根碱(Jat)与牛血清白蛋白(BSA)相互作用的光谱特性.结果表明:Jat对于BSA荧光猝灭主要是静态猝灭和非辐射能量转移;Jat浓度增大,BSA荧光峰被猝灭的同时出现峰裂分现象,原来345 nm处的单峰逐渐裂分为二重峰,其中一峰峰值蓝移,另一峰峰值红移至λcm=362～365 nm;测...     

The interaction between bovine serum albumin and the self-aggregated nanoparticles of cholesterol-modified O-carboxymethyl chitosan

The interaction between bovine serum albumin (BSA) and self-aggregated nanoparticles of cholesterol-modified O-carboxymethyl chitosan (CCMC) with different degrees of substitution (DS) of cholesterol moiety was studied by transmission electron microscopy (TEM), fluorescence quenching method and circular dichroism (CD) measurement. This interaction was started at the disaggregation of CCMC self-aggregated nanoparticles and reached equilibrium after 3-4 h. The apparent quenching constant (K_q) between BSA and CCMC self-aggregated nanoparticles calculated by the modified Stern-Volmer plot increased from 4.14 × 10⁴ to 1.95 × 10⁵ M⁻¹ with DS of cholesterol moiety increasing from 3.2% to 9.8%, whereas the fraction of tryptophan residues in BSA molecule involved in the interaction decreased at the same time. Compared with free BSA, the relative α-helix content of BSA decreased and the unfolding of BSA by a denaturant such as urea was largely suppressed upon interaction with CCMC self-aggregated nanoparticles. DS of cholesterol moiety significantly affected the interaction between BSA and CCMC self-aggregated nanoparticles.     

Double-perovskite magnetic La2NiMnO6 nanoparticles for adsorption of bovine serum albumin applications

Double-perovskite La₂NiMnO₆ (LNMO) nanoparticles were synthesized by co-precipitation process, and the adsorption of bovine serum albumin (BSA) protein on these nanoparticles was carried out. The powder samples were annealed at 750, 850, 950, and 1,050°C, respectively. X-ray diffraction (XRD) results reveal that there are double perovskites and exhibit mixed orientations, without any impurity phases. Transmission electron microscopy results as well as the XRD estimate results show that the crystalline size is about 34 to 40 nm. The adsorption of BSA on the magnetic nanoparticles was analyzed using a UV spectrophotometer at room temperature. The results show that the as-prepared LNMO nanoparticles display a good adsorbing ability for BSA, and the nanoparticle sintered at 850°C has the highest value of 219.6 mg/g, which is much higher than others.     

荜茇宁与牛血清白蛋白相互作用的研究

用荧光光谱及紫外光谱法研究生理条件下荜茇宁与生物大分子牛血清白蛋白(BSA)的相互作用.实验结果表明,荜茇宁与BSA形成基念复合物从而猝火BSA的内源性荧光,猝灭原因主要为静态猝灭和非辐射能量转移.根据Forster 偶极-偶极非辐射能量转移理论,确定荜茇宁与BSA有较强的相互作用,可以被蛋白质所储存和运输.荜茇宁与B...     

有机氯农药与牛血清白蛋白作用机理研究

利用荧光光谱法研究了5种有机氯农药（OCPs） δ-BHC、α-氯丹、艾氏剂、o,p＇-DDT、HCB和牛血清白蛋白（BSA）的相互作用机理.280 nm波长下,OCPs可使BSA色氨酸残基发生荧光猝灭现象.通过光谱数据,绘制了Stern-Volmer曲线,测定了平衡常数和25,37℃下OCPs-BSA的结合常数.结果显示,5种OCPs猝灭蛋白质的过程均为熵驱动的静态猝灭过程,通过较弱的疏水作用力与蛋白质相互结合,结合点位数近似为1,这种结合作用会随着温度的升高而增强.     

牛血清白蛋白的荧光稳定性研究

研究了牛血清白蛋白(BSA)在不同条件下荧光发射光谱的稳定性。结果表明,Tris-HCl、PBS和PB等缓冲液种类,常量和微量等石英比色皿类型,对于BSA的荧光稳定性没有明显影响。激发波长260 nm与280 nm对于BSA的荧光稳定性有显著性差异。超声和金属离子的干扰,都会导致BSA荧光强度的降低,在5%的误差范围内,各金属离子允许存在的倍数分别为:Cu2+(8),Zn2+(40),Mg2+(96),Ca2+(120)。本研究对于蛋白质溶液的制备和前处理具有一定的理论和实际意义。