Synthesis and Characterization of Thermally Stable Lignosulfonamides

Lignin, a highly aromatic macromolecule building plant cells, and cellulose are two of the most commonly occurring natural polymers. Lignosulfonate is a grade of technical lignin, obtained as a by-product in the paper and wood pulping industries, a result of the used lignin isolation method, i.e., sulfite process. In this work, sodium lignosulfonate is used as a starting material to manufacture sulfonamide derivatives of lignin in a two-step modification procedure. Since this direction of the lignin modification is rather rarely investigated and discussed, it makes a good starting point to expand the state of knowledge and explore the properties of lignosulfonamides. Materials obtained after modification underwent characterization by FTIR, SS-NMR, WAXD, SEM, and TGA. Spectroscopic measurements confirmed the incorporation of dihexylamine into the lignin structure and the formation of lignosulfonamide. The crystalline structure of the material was not affected by the modification procedure, as evidenced by the WAXD, with only minute morphological changes of the surface visible on the SEM imaging. The obtained materials were characterized by improved parameters of thermal stability in relation to the raw material. As-prepared sulfonamide lignin derivatives with a potential application as a filler in biopolymeric composites may become a new class of functional, value-added, sustainable additives.     

Preparation and Characterization of Novel Quaternized Cellulose Nanoparticles as Protein Carriers

Quaternized cellulose (QC) nanoparticles were prepared in distilled water by ionic crosslinking of QC with sodium tripolyphosphate (TPP) for the first time. BSA as a model protein drug was used to investigate the loading and release features of the nanoparticles. The results indicated that QC nanoparticles had high loading efficiency and capacity for BSA. The in vitro BSA release of the QC nanoparticles displayed a burst effect in the first 2 h and then a slow continuous release. Nanoparticles with a higher DS of QC showed a decrease in particle size, an increase in zeta potential, a higher loading efficiency and a slower drug‐release profile. These studies demonstrated that QC nanoparticles are potential protein carriers, and that their physicochemical properties and release profile could be easily adjusted.

     

翻译后修饰Tau蛋白及其化学全/半合成

Tau蛋白是一种微管相关蛋白,有6种亚型,由352～441氨基酸组成。Tau蛋白的错误折叠和聚集与Tau蛋白病(Tauopathies),如阿尔茨海默病(AD)密切相关。目前在临床患者样本中可检测到具有各种翻译后修饰的Tau蛋白,这些翻译后修饰可能是AD发病机制的关键因素。本文综述了Tau蛋白常见的翻译后修饰,尤其是退行性疾病相关的翻译后修饰,以及化学全/半合成制备具有特定位点修饰、均一的Tau蛋白的进展。通过回顾翻译后修饰Tau蛋白的研究,可以更深入理解翻译后修饰对Tau蛋白的生理和病理作用,阐明翻译后修饰的调控机制,为相关疾病诊疗研究打下基础。     

卵清蛋白与离子型表面活性剂的相互作用

本文通过荧光光谱法、紫外-可见吸收光谱法和透射电镜并结合电导率测定分别研究了水中卵清蛋白与阴离子表面活性剂十二烷基硫酸钠（SDS）和阳离子表面活性剂十二烷基三甲基溴化铵（DTAB）和十六烷基三甲基溴化铵（CTAB）之间的相互作用。研究结果表明卵清蛋白可以增加SDS和CTAB的临界胶束浓度,但对DTAB的临界胶束浓度没有影响。阴离子表面活性剂可以使卵清蛋白构象完全伸展,而阳离子表面活性剂却不具备此种作用。表面活性剂单体与卵清蛋白的相互作用强于表面活性剂胶束与卵清蛋白的相互作用。     

N－(4-羟基-3-甲氧基苯甲基）壳聚糖的制备及其水凝胶的pH敏感性

N－(4-羟基-3-甲氧基苯甲基）壳聚糖的制备及其水凝胶的pH敏感性;壳聚糖;改性;pH敏感性;水凝胶;溶胀度;释药     

Synthesis and Characterisation of Self‐Assembled and Self‐Adjuvanting Asymmetric Multi‐Epitope Lipopeptides of Ovalbumin

Designing a lipopeptide (LP) vaccine with a specific asymmetric arrangement of epitopes may result in an improved display of antigens, increasing host‐cell recognition and immunogenicity. This study aimed to synthesise and characterise the physicochemical properties of a library of asymmetric LP‐based vaccine candidates that contained multiple CD4⁺ and CD8⁺ T‐cell epitopes from the model protein antigen, ovalbumin. These fully synthetic vaccine candidates were prepared by microwave‐assisted solid phase peptide synthesis. The C12 or C16 lipoamino acids were coupled to the N or C terminus of the OVA CD4 peptide epitope. The OVA CD4 LPs and OVA CD8 peptide constructs were then conjugated using azide–alkyne Huisgen cycloaddition to give multivalent synthetic vaccines. Physiochemical characterisation of these vaccines showed a tendency to self‐assemble in aqueous media. Changes in lipid length and position induced self‐assembly with significant changes to their morphology and secondary structure as shown by transmission electron microscopy and circular dichroism.     

医用高分子水凝胶的设计与合成

作为一类重要的医用功能材料,高分子水凝胶可望在药物控释、软骨支架构建、活性细胞封装等方面获得广泛应用。综述了基于化学交联和物理交联的有关水凝胶的设计与合成方法,重点介绍了通过自由基共聚反应、结构互补基团间化学反应形成的化学交联水凝胶以及通过荷电相反离子问相互作用、两亲性嵌段或接枝共聚物疏水缔合、结晶与氢键相互作用形成的物理交联水凝胶。     

A Study of the Swelling Properties of Polymer Nanocomposites through Electrical and Optical Characterization

In the present study, polymer nanocomposite layers for sensing applications are characterized by means of an optical method based on white light interferometry. The study focuses on poly (hydroxy ethyl methacrylate) (PHEMA) and on nanocomposite Carbon black (CB)/PHEMA layers commonly used in chemical sensor technology for volatile organic compounds (VOCs) detection. The interferometric spectra of these two different materials, recorded during analyte exposure, are analyzed in terms of film expansion. Comparison between PHEMA and PHEMA/CB layer shows that the nanocomposite undergoes a more pronounced swelling process. In order to achieve a better comprehension of the sensing mechanism and to improve the sensor performances, the variations of the electrical signal of a nanocomposite-based chemiresistor in presence of VOCs are examined and compared to the optical behaviour.     

6-马来酰亚胺基己酸的合成与表征

以氨基己酸和马来酸酐为原料,乙酸酐、乙酸钠作催化剂,在室温下反应5h,合成了一种新的可用于蛋白质、多肽药物修饰的“间隔臂”6-马来酰亚胺基己酸,产率90．34％,其结构经。HNMR,IR和LC-MS表征。     

Synthesis and radical polymerization behavior of bifunctional vinyl monomer derived from N‐vinylacetamide and p‐chloromethylstyrene

The radical polymerization of N‐(p‐vinylbenzyl)‐N‐vinylacetamide ( 1 ) prepared by the reaction of N‐vinylacetamide with p‐chloromethylstyrene was carried out by using radical initiators such as AIBN or BPO in benzene, chlorobenzene, or bulk. As a result, poly 1 was successfully isolated by dialysis (yield, 10–36%). The crosslinking reaction of poly 1 was carried out at 60–100 °C for 8 h. By using a radical initiator such as AIBN or BPO (3 mol %), the crosslinking reaction proceeded (yield, 63–79%). Moreover, the crosslinking reaction of poly 1 proceeded at 100 °C without a radical initiator in 50% yield. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2714–2723, 2006     

大豆分离蛋白甲基丙烯酸接枝共聚物的合成与表征

以过硫酸铵为引发剂、2-巯基乙醇为蛋白质变性剂,在浓度为8mol／L尿素溶液中进行了大豆分离蛋白与甲基丙烯酸的接枝共聚反应;傅里叶红外光谱和核磁共振谱证明,甲基丙烯酸成功地接枝到了大豆分离蛋白上;相关影响因素的单因数实验研究表明,各因数的最佳值分别为：引发剂浓度16mmol／L,单体浓度2．4mol／L,反应温度80℃,反应时间4h,巯基乙醇浓度0．05mol／L。     

Cysteine/Penicillamine Ligation Independent of Terminal Steric Demands for Chemical Protein Synthesis

The chemical ligation of two unprotected peptides to generate a natural peptidic linkage specifically at the C‐ and N‐termini is a desirable goal in chemical protein synthesis but is challenging because it demands high reactivity and selectivity (chemo‐, regio‐, and stereoselectivity). We report an operationally simple and highly effective chemical peptide ligation involving the ligation of peptides with C‐terminal salicylaldehyde esters to peptides with N‐terminal cysteine/penicillamine. The notable features of this method include its tolerance of steric hinderance from the side groups on either ligating terminus, thereby allowing flexible disconnection at sites that are otherwise difficult to functionalize. In addition, this method can be expanded to selective desulfurization and one‐pot ligation‐desulfurization reactions. The effectiveness of this method was demonstrated by the synthesis of VISTA (216‐311), PD‐1 (192‐288) and Eglin C.     

蛋白质修饰的电化学研究

蛋白质的翻译后修饰对于生命体执行正常的生理功能具有十分重要的作用,是蛋白质科学研究的重要内容.目前研究蛋白质修饰的方法主要有质谱法、亲和层析等,然而由于蛋白质修饰研究的复杂性,迫切需要发掘新的技术手段.电化学方法理论成熟、应用广泛,在生命科学许多领域发挥着越来越重要的作用.蛋白质的体外修饰必将导致蛋白质特定位点基团的变化,可以利用巧妙设计的电化学方法予以表征和分析,以期探明修饰对蛋白质结构和功能的影响.此外,又可以利用电化学定量分析的独特优势快速准确地测定蛋白质修饰中涉及的相关酶活.正因为如此,蛋白质体外修饰的电化学研究已引起越来越多的关注.本文以作者课题组近期研究工作为主,结合国内外同行的相关代表性工作,介绍电化学方法在蛋白质修饰方面的近期研究进展,并探讨了今后的发展方向和趋势.     

Synthesis and crosslinking of biphenyl and naphthalene liquid‐crystalline polyethers with pendant full‐saturated and vinyl‐terminated aliphatic chains

Two series of vinyl‐terminated, side‐chain liquid‐crystalline polyethers containing 4,4′‐biphenyl and 2,6‐naphthalene moieties as mesogenic cores with several contents of vinyl crosslinkable groups were synthesized by chemically modifying poly(epichlorohydrin) with mixtures of saturated and vinyl‐terminated mesogenic acids. In most cases the degree of modification was over 90%. The polymers were characterized by chlorine analysis, IR and ¹H and ¹³C NMR spectroscopies, viscometry, size exclusion chromatography/multi‐angle laser light scattering, and thermogravimetric analysis. The liquid‐crystal behavior of all the synthesized polymers was examined by differential scanning calorimetry, polarized optical microscopy (POM), and X‐ray diffraction on mechanically oriented samples. The crosslinking of most polymers was done by peroxide‐type initiators, which generally led to liquid‐crystal elastomers. The mesophase organization was maintained on the crosslinked materials, as confirmed by POM and X‐ray diffraction. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3384–3399, 2003     

温敏性PCL-PEG-PCL水凝胶的合成、表征及蛋白药物释放

考察了温敏性PCL-PEG-PCL水凝胶中聚乙二醇(PEG)及聚己内酯(PCL)不同嵌段组成对其溶胶-凝胶相转变温度以及亲水性药物(牛血清白蛋白, BSA)释放速率的影响. 采用开环聚合法, 以辛酸亚锡为催化剂、PEG1500/PEG1000为引发剂, 与己内酯单体发生开环共聚, 合成了一系列具有不同PEG和PCL嵌段长度的PCL-PEG-PCL型三嵌段共聚物. 通过核磁共振氢谱及凝胶渗透色谱对其组成、结构及分子量进行了表征. 共聚物的溶胶-凝胶相变温度由翻转试管法测定. 利用透射电镜、核磁共振氢谱及荧光探针技术证实了该材料在水溶液中胶束的形成. 以BSA为模型蛋白药物, 制备载药水凝胶, 利用microBCA法测定药物在释放介质中的浓度, 研究其体外释放行为. 实验结果表明, 共聚物的溶胶-凝胶相变温度与PCL及PEG嵌段长度紧密相关, 即在给定共聚物浓度情况下, 固定PEG嵌段长度而增加PCL嵌段长度, 会导致相变温度降低; 而固定PCL嵌段长度而增加PEG嵌段长度, 其相变温度相应升高. 水凝胶中蛋白药物的释放速率与疏水的PCL嵌段长度无关, 而与亲水的PEG嵌段长度密切相关, 即PEG嵌段越长, 蛋白药物释放越快.     

Synthesis and Characterization of Crosslinked Hyperbranched Polyglycidol Hydrogel Films

Hyperbranched polyglycidol (PGLD) was synthesized via anionic ring‐opening polymerization of glycidol using a special anionic initiator with multiple initiation sites. The resultant polymers were characterized by ¹H and ¹³C‐NMR spectra for confirming their structures, which consisted of linear, hyperbranched and dendritic structures. Molecular weight characteristics were determined by means of the gel permeation chromatography (GPC). With the intention of investigating the possibility of broad applications, PGLD hydrogel films were prepared using various crosslinking agents, i.e., glutaraldehyde and some dicarboxylic acids, and their physical properties such as swelling behavior and tensile (or Young's) modulus were measured and compared.     

蛋白质高分子结合体

蛋白质高分子结合体是蛋白质与高分子化合物以特定位置或方式结合的产物。其中,蛋白质(包括酶和多肽)分子中氨基酸残基上的氨基、巯基和羧基是常用的结合位点。本文主要对蛋白质高分子结合体的制备方法进行了综述。聚乙二醇是合成高分子中能够有效改善蛋白质性能的修饰剂,而多糖则是用于制备蛋白质高分子结合体较成功的天然高分子化合物。“点击化学”、活性聚合技术等技术已经被成功应用于蛋白质高分子结合体的制备。某些具有特异结合功能基团的化合物(如金属卟啉、生物素等)与高分子共价结合后也可制备蛋白质高分子结合体。在研究蛋白质高分子结合体制备方法的基础上,近年来开始了这类大分子的自组装行为研究,尤其是对巨型双亲性分子自组装行为的研究,这为设计和构筑先进功能材料提供了新的思路。与高分子化合物的结合是改善蛋白质性能和拓宽蛋白质应用范围的重要技术之一。蛋白质高分子结合体不但可用于生物医药领域,而且在纳米技术和材料科学等领域具有潜在的优势。     

树枝状偶氮液晶高分子(PAMAM-MMAZO)的合成及表征

树枝状偶氮液晶高分子(PAMAM-MMAZO)的合成及表征;树枝状聚酰胺-胺;树枝状偶氮液晶;表面修饰;液晶性