溶菌酶在羊毛表面的静电自组装固定化及其抗菌性能

通过层层静电自组装法将溶菌酶和聚苯乙烯磺酸钠(PSS)交替沉积在羊毛纤维表面, 赋予其抗菌性. 应用扫描电镜(SEM)考察组装后纤维表面形态, Zeta电位、染色、溶菌酶活性测试研究纤维表面组装机制并考察改性羊毛抗菌效果. SEM结果表明组装后纤维表面粗糙, 部分凹槽被填埋, 证明溶菌酶/PSS自发组装到纤维表面. 表面电位、染料上染量、溶菌酶活力随纤维表面沉积物质不同, 均呈现明显的“层层交替振荡”现象, 证实了组装后纤维表面电荷的交替变化|织物紫外线透过率随组装层数增加呈近似线性降低, 表明溶菌酶在羊毛表面实现了多层组装, 揭示了羊毛纤维表面抗菌功能涂层的层层静电自组装构筑机制. 同时, 组装层数增多, 溶菌酶活性逐渐增大. 载酶羊毛抗菌率达到91.7%, 具有良好的抗菌性能.     

碲化镉量子点自组装膜的构建及其对溶菌酶的界面传感

利用自组装膜(SAMs)技术在石英片表面构建了碲化镉量子点SAMs.考察了组装液浓度、组装时间和聚电解质组装层数等组装条件对膜发光性能的影响,并用紫外可见吸收光谱仪、荧光光谱仪、共聚焦荧光显微镜和原子力显微镜对其进行了表征.基于溶菌酶对该SAMs的荧光具有猝灭效应,建立了一种快速灵敏测定痕量溶菌酶的界面荧光分析法,线性...     

动态多孔海绵结构多层膜负载溶菌酶用于抗菌涂层的研究

以聚丙烯酸(PAA)和聚乙烯亚胺(PEI)为构筑单元,运用层层自组装技术制备了聚电解质多层膜.该多层膜具有独特的动态特点——经酸处理后膜内部形成海绵状通孔结构,该海绵结构在饱和水蒸气的处理下,多孔结构能够闭合,重新回到致密的膜结构.借助该种动态多层膜平台,能够简单有效地通过毛细作用力将溶菌酶负载并固定于多层膜中,为制备基于抗菌蛋白的抗菌涂层提供了新的方法.扫描电镜表征了多层膜动态变化过程,激光共聚焦显微镜表征了溶菌酶在膜内的分布情况,并测定了溶菌酶载入量及其释放动力学.进一步的抗菌测试表明该种抗菌涂层在溶菌酶和PEI的共同作用下可以有效地抑制金黄色葡萄球菌.将多层膜同时负载溶菌酶和乳铁蛋白,提升了涂层对大肠杆菌的杀菌效果.     

基于透明质酸生物活性自组装胶体粒子制备及乳化性能

用透明质酸(HA)和溶菌酶(Lys)静电自组装制备胶体粒子。研究了溶菌酶和透明质酸的质量比(WR)对胶体粒子性质的影响,得到最佳质量比下的胶体粒子。用纳米粒度仪和透射电镜对胶体粒子的尺寸和形貌进行表征。结果显示,形成的胶体粒子为球形结构,粒径约250 nm。此胶体粒子可二次组装在油水界面稳定水包油型类凝胶Pickering乳液。详细研究了pH和盐浓度对胶体粒子性质和乳化性能的影响。结果表明,随着pH增加,胶体粒子粒径先减小后增加;乳液滴粒径逐渐减小,乳化性能逐渐增加。随着盐浓度增加,胶体粒子和乳液滴粒径先降低后增加,乳化性能先增加后降低。进一步研究了pH和盐浓度对乳液中溶菌酶活性的影响。研究表明,制备的乳液均保留了一定的活性,在食品、医药和化妆品领域具有潜在的应用。     

应用纳米球刻蚀法在自组装膜修饰的硅表面生成中尺度的网状蛋白层（英文）

在自组装膜修饰的硅表面制备有序的蛋白阵列是研发生物传感器的先决条件之一,因此如何产生有序的表面蛋白阵列一直是生物医药研究方向的前沿。本研究通过应用纳米球刻蚀法在氧化的10-烯基十一烷基三氯硅烷自组装膜修饰的硅表面生成了网状结构溶菌酶蛋白层。网孔的大小(从纳米到微米级别)由表面沉积的纳米球的尺寸来调控。我们利用原子力显微镜和荧光显微镜对样品表面进行了详细表征。结果表明:这种新方法比传统的通过扫描探针在固体表面修饰而聚集溶菌酶蛋白的方法更快捷简便,而且它能够在相对大的硅表面形成网状蛋白层。此外,网孔表面附着具有强吸附活性的羧酸基团层,它可以通过静电吸引或者共价结合来吸附液相中的第二种蛋白分子。     

一种阳离子交换磁性多壁碳纳米管复合材料及其蛋白质的吸附性能研究

本研究首先制备了磁性氨基化多壁碳纳米管,然后通过静电自组装的方法将聚丙烯酸修饰在其表面,得到了一种新型阳离子交换磁性吸附剂。通过红外光谱、透射电镜、X射线光电子能谱对该吸附剂进行了表征。以溶菌酶和细胞色素c为模型蛋白,采用静态吸附法研究了该吸附剂对蛋白质的吸附性能,并测定了静态吸附等温线。结果表明:吸附剂对蛋白质的最佳吸附时间为1 h,缓冲液的最佳pH值为6.0。在此条件下,对溶菌酶和细胞色素c的最大吸附容量分别为237.5、204.5μg/mg,而对牛血清白蛋白几乎不产生吸附。因此,吸附剂对碱性蛋白质具有较高的吸附容量和选择性。最后,将吸附剂用于鸡蛋清中溶菌酶的分离纯化,获得了较高的纯度。     

光谱法研究鸡蛋溶菌酶热变性与免疫原性的关系

利用圆二色性光谱和荧光光谱对鸡蛋溶菌酶的热变性过程进行了系统的光谱学研究,得到了鸡蛋溶菌酶热变性过程的光谱学特征;通过酶联免疫吸附实验测定鸡蛋溶菌酶热变性过程的免疫原性变化;结合生物信息学方法,分析了热变性过程中鸡蛋溶菌酶蛋白结构改变与其免疫原性变化之间的关系,建立研究食品过敏原蛋白热变性的光谱学方法.     

CdSe量子点探针共振光散射法检测溶菌酶

基于CdSe量子点与溶菌酶之间的相互作用, 采用共振光散射法建立了简单快速检测溶菌酶的新方法. 在优化的实验条件下, 当溶菌酶浓度在0.01~0.8 μmol/L范围内变化时, 散射光强度与溶菌酶浓度间呈现良好的线性关系, 相关系数为0.9960. 此方法对溶菌酶的检出限为5.2 nmol/L, 对0.09 μmol/L溶菌酶5次平行测定的相对标准偏差为2.1%, 此方法选择性较好, 常见离子、蛋白质及常见氨基酸对溶菌酶检测干扰较小, 这种新方法已被用于合成样品中溶菌酶的检测, 并取得较好结果. 为进一步考察CdSe量子点与溶菌酶之间的相互作用, 进行了圆二色光谱、透射电子显微镜和荧光寿命表征研究, 结果表明, CdSe量子点与溶菌酶的结合不仅使溶菌酶的构象发生变化, 也使CdSe量子点的分散状态和荧光寿命发生了改变.     

表没食子儿茶素(EGC)对溶菌酶淀粉样纤维化的抑制作用

天然多酚化合物是蛋白质淀粉样纤维化相关疾病的潜在治疗药物。本文采用溶菌酶和表没食子儿茶素(EGC)研究了多酚化合物对蛋白质淀粉样纤维的作用。结果表明,EGC能够抑制溶菌酶的淀粉样纤维化,并能够破坏成熟的纤维结构,使纤维的淀粉样特性降低。巯基化合物二巯基苏糖醇(DTT)能够部分抑制EGC破坏纤维的作用,表明EGC可能通过与巯基结合而对多肽链进行共价修饰,从而改变了淀粉样纤维的自组装结构。根据上述结果,我们认为,多酚化合物形成醌类中间体并对多肽链的自由巯基进行修饰,是其抑制蛋白质淀粉样纤维化的主要途径。     

盐酸胍和尿素诱导溶菌酶变性的微量热研究

应用恒温微量热技术,对盐酸胍和尿素与溶菌酶在30℃水溶液中的结合作用及造成溶菌酶变性的过程进行了研究,并根据简单结合模型,计算了它们之间的结合常数、结合自由能。用变性中点的直线外推方法求出了表观变性焓。实验结果表明,盐酸胍和尿素诱导溶菌酶变性的相互作用均分为3个阶段。溶菌酶在盐酸胍溶液中的变性焓在pH=4.16时为81...     

PLA/MWNTs/HA复合材料的制备和性能研究

采用超声辅助原位湿法合成多壁碳纳米管／羟基磷灰石纳米复合材料(MWNTs／HA),并通过溶液浇铸法制备了PLA／MWNTs／HA复合材料薄膜。考察了MWNTs／HA纳米粒子含量对复合膜性能的影响,并通过力学性能、SEM、FTIR、以及DMTA对复合膜性能进行了表征,结果表明：随着纳米粒子质量分数的增加,复合膜的拉伸强度呈下降趋势;拉伸模量和储能模量呈现先下降后上升的趋势;玻璃化转变温度则呈现不断上升趋势。     

Manganese Dioxide Graphite Composite Electrodes Formed via a Low Temperature Method: Detection of Hydrogen Peroxide,Ascorbic Acid and Nitrite

Manganese dioxide modified carbon powder was prepared via a wet impregnation method from the solution of permanganate salt. After heating at 120 °C over night in air, the formation of manganese oxide was confirmed by cathodic stripping voltammetry. The synthesized material was used for fabrication of composite electrodes and their potential application in the field of electroanalysis investigated. The composite electrodes based on the manganese dioxide modified carbon powder proved to be useful as electrodes for detection of hydrogen peroxide, ascorbic acid and nitrite ions.     

功能性CdSe纳米晶的合成及自组装膜光致发光

以巯基丙酸(RSH)为稳定剂,采用湿化学法合成了功能性CdSe纳米晶,用XRD、TEM表征其粒度和形貌,用UV-Vis监测成核及成膜过程。结果表明：制得的CdSe近似呈球形,平均粒径为48 nm。利用静电自组装法层层组装成CdSe-PDDA复合膜,荧光测试表明：所得CdSe纳米晶自组装复合膜(CdSe-PDDA)的荧光强度随着组装层数的增加而呈线性增强,该复合膜在582 nm附近有黄绿色荧光发射。     

Polymer‐supported palladium: A hybrid system for multifunctional catalytic application

Polymer‐supported palladium was synthesized by applying a single‐step wet chemical synthesis route and the resultant composite material was characterized by means of various techniques. Infrared and UV–visible spectra provided information on the chemical structure of the polymer. Microscopy techniques showed the general morphology of the polymer. The oxidation state of palladium was determined using the X‐ray photoelectron spectroscopy method. The synthesized material was applied as a heterogeneous catalyst for the Heck coupling reaction and also as an electrocatalyst for the oxidation of cysteine.     

球磨方式对锂离子正极材料LiFePO4性能的影响

采用高温固相合成法制备橄榄石型的LiFePO₄正极材料，在合成过程中分别采用湿法球磨和干法球磨两种球磨方式。用X-射线衍射，扫描电镜，激光粒度测试等对合成材料进行表征，并对以LiFePO₄为正极的电池进行电化学性能测试。结果表明，相对于干法球磨，湿法球磨制备的LiFePO₄样品具有更好的电化学性能，0.2C放电的首次放电比容量为134.9 mAh·g^-1，并有优良的大电流放电性能及循环性能。这主要是因为采用湿法球磨制备的LiFePO₄材料物相较纯、粒径均匀，与导电添加剂的接触更加紧密，从而提高了LiFePO₄材料电化学性能。     

基于发光金纳米粒子荧光增强法测定溶菌酶

参照文献方法合成了BSA修饰的水溶性发光金纳米粒子,并考察了其与溶菌酶之间的相互作用.依据溶菌酶对金纳米粒子的发光增强现象,建立了测定溶菌酶的荧光新方法.考察了发光金纳米粒子的浓度、pH值、反应时间及共存物质对测定的影响.优化条件为:发光金纳米粒子浓度4.0×10(-6)mol/L,pH 7.0、反应时间10 min....     

Determination of Lysozyme by Graphene Oxide–Polyethylene Glycol-Based Fluorescence Resonance Energy Transfer

The surface of graphene oxide was modified by bis(3-aminopropyl)-terminated polyethylene glycol to produce a composite graphene–polyethylene glycol. The graphene oxide/polyethylene glycol maximum absorption peak in the ultraviolet–visible spectrum was redshifted, and transmission electron microscope images showed that graphene oxide was cleaved into small nanosheets to form graphene oxide/polyethylene glycol. The dispersibility of graphene oxide/polyethylene glycol in physiological solution was higher than for graphene oxide. The optimum composite of graphene oxide/polyethylene glycol was used as a quencher in a fluorescence resonance energy transfer aptasensor for the determination of lysozyme detection. The results showed that graphene oxide/polyethylene glycol rapidly and efficiently quenched the fluorescence of the dye-labeled aptamer. The fluorescence was recovered by adding lysozyme to the system. The aptamer fluorescence intensity exhibited a strong linear dependence on the lysozyme concentration from 50 to 300?nM, and the lysozyme detection limit was approximately 11?nM. This method was used for the determination of lysozyme in egg whites, demonstrating that this approach is a promising alternative for the determination of lysozyme.     

Multifunctional nanoparticles composite for MALDI-MS: Cd2+-doped carbon nanotubes with CdS nanoparticles as the matrix, preconcentrating and accelerating probes of microwave enzymatic digestion of peptides and proteins for direct MALDI-MS analysis

For the first time, we utilized multifunctional nanoparticles composite (NPs composite) for matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analysis of peptides and proteins. Multiwalled carbon nanotubes doped with Cd(2+) ions and modified with cadmium sulfide NPs were synthesized by a chemical reduction method at room temperature. The multifunctional NPs composite applied for the analysis of peptides and microwave-digested proteins in the atmospheric pressure matrix-assisted laser desorption/ionization ion-trap and MALDI time-of-flight (TOF) mass spectrometry (MS) was successfully demonstrated. The maximum detection sensitivity for peptides in MALDI-MS was achieved by the adsorption of negatively charged peptides onto the surfaces of NP composite through electrostatic interactions. The optimal conditions of peptide mixtures were obtained at 20 min of incubation time using 1 mg of NPs composite when the pH of the sample solution was kept higher than the pI values of peptides. The potentiality of the NP composite in the preconcentration of peptides was compared with that of the individual NP by calculating the preconcentration factors (PF) and found that the NPs composite showed a 4-6 times of PF than the other NPs. In addition, the NPs composite was also applied as heat-absorbing materials for efficient microwave tryptic digestion of cytochrome c and lysozyme from milk protein in MALDI-TOF-MS analysis. We believe that the use of NPs composite technique would be an efficient and powerful preconcentrating tool for MALDI-MS for the study of proteome research.     

Synthesis of Monodisperse Poly（glycidylmethacrylate-co-ethylene dimethacrylate） Beads and Their Application in Separation of Biopolymers

Introduction Since 19541 the polymeric separation media has attracted much attention due to their chemical stability over the entire pH range. The rigid, highly cross-linked styrene copolymers were first used for chromatography by Moore.2 The macroporous copolymers currently available are not only chemically stable but also more resistant to mechanical forces prevailing in a column and therefore are comparable to the traditional packings based on silica gel. Most polymer separation media are …     

Preparation of Medium Cation Exchange Stationary Phase of Polymeric Matrix and Their Chromatographic Properties

Based on the monodisperse poly（glycidyl methacrylate-co-ethylenedimethacrylate） beads （PGMA/EDMA） with macropore as a medium, a new hydrophilic medium cation exchange （MCX） stationary phase for HPLC was synthesized by a new chemically modified method. The stationary phase was evaluated with the property of ion exchange, separability, reproducibility, hydrophilicity, effect of salt concentration, salt types, column loading and pH on the separation and retention of proteins in detail. It was found that it follows ion exchange chromatographic （IEC） retention mechanism. The measured bioactivity recovery for lysozyme was （96 ± 5）%. The dynamic protein loading capacity of the synthesized MCX packings was 21.8 mg/g. Five proteins were almost completely separated within 6.0 min at a flow rate of 4 mL/min using the synthesized MCX resin. The MCX resin was also used for the rapid separation and purification of lysozyme from egg white with only one step. The purity and specific bioactivity of the purified lysozyme was found more than 95% and 70345 U/mg, respectively.