Understanding effects of sulphation of physical and chemical characteristics of polysaccharides: new renewable biopolymers for personal care products

碳水化合物来源于植物和动物，由于其物理、化学和相互作用特性，具有许多自然和商业应用。由于碳水化合物的改性导致了这些性质的可观察到的差异，因此改性后的样品已用于从药剂到乳剂和食品成分的各种应用中。本项目将使用几种碳水化合物作为线性不带电、线性带电和支链不带电的代表性例子。该项目将致力于改进基于核磁共振的碳水化合物分析方法，生成新的碳水化合物修饰和修饰方法，以及测量修饰样品的物理、化学和相互作用性质。碳水化合物表征可以确定起始物质结构，确定任何修饰和相互作用位点。核磁共振（NMR）是最强大和通用的碳水化合物结构分析方法，需要改进方法来允许单个原子分配。将这种方法与其他方法相结合，例如粒径排除色谱法和质谱法，以及碳水化合物核磁共振扩散光谱领域的最新发展，将允许对那些能够分离或区分不同大小的馏分的方法进行比较，并协助结构表征。这些组合的方法也将允许重复单元分布和这些单元出现的频率被确定。改性明显地影响了本项目中使用的碳水化合物的物理化学和相互作用特性。对所选的每一种碳水化合物，将进行一系列的修饰，重点是通过磺化、氧化成羧基和还原来增加碳水化合物的电荷。对生成的改性产物的分析将使用上述开发的基于核磁共振的结构分析方法，并确定改性位点的精确位置。还将研究可能影响修饰位点的其他因素，以确定在开发新方法而不是传统方法时是否可以靶向特定的原子位置。以前的碳水化合物改性已经研究了它们对样品的物理和化学性质的影响。由于我们的工业合作伙伴在商业领域的潜在应用，这些特性的主要重点将放在流变测量上。其他重要的物理和化学性质包括溶解度、粘度、分子迁移率、沉积和清洁。在我们的商业合作伙伴的实验室以及大学的核磁共振光谱仪的放置期间，可以测量许多这些属性。除了碳水化合物改性对所得样品的物理和化学性质的影响外，碳水化合物与它可能遇到的其他化合物相互作用的能力也有明显的影响。修饰对这些相互作用的影响也将通过对蛋白质、其他碳水化合物和/或表面活性剂分子的几种测试系统进行研究。在某些情况下，使用结构分析方法对相互作用变异性的研究将与生物测定相结合。从结构上研究这些相互作用需要将NMR与其他常用方法（如等温滴定量热法和圆二色法或差示扫描荧光法/量热法）相结合，在添加改性多糖时分别生成动力学和蛋白质稳定性数据。

Carbohydrates, derived from plant and animal sources, have many natural and commercial applications arising from their physical, chemical and interaction properties. As carbohydrate modifications have resulted in observable differences to these properties, modified samples have been used in various applications from pharmaceutical agents to emulsions and food components. Several carbohydrates will be used during this project as representative linear uncharged, linear charged and branched uncharged examples. The project will target improving NMR-based carbohydrate analysis methods, the generation of novel carbohydrate modifications and modification methods, and the measurement of the physical, chemical and interaction properties of modified samples.Carbohydrate characterisation enables the starting material structure to be ascertained and any modification and interaction sites determined. Nuclear Magnetic Resonance (NMR) is the most powerful and versatile structural analysis method for carbohydrates and requires methodological improvements to allow individual atom assignments to be made. Combining this with additional methods, such as size exclusion chromatography and mass spectrometry, as well as recent developments in the field of carbohydrate NMR via diffusion spectroscopy, will allow comparison of those methods that are able to separate of distinguish the different sized fractions, and assist structural characterisation. These combined methods will also allow the repeating unit distribution the frequency with which these units occur to be determined.Modifications have demonstrably affected the physical chemical and interaction properties of the carbohydrates used in this project. A panel of modifications focusing on the addition of charges to the carbohydrate via sulphation, oxidation to carboxyl groups but also reduction, will be performed on each of the carbohydrates selected. The analysis of modified products generated will be performed using the NMR-based structural analysis method developed above with the precise location of modification sites determined. Additional factors that could influence modification sites will also be investigated to determine whether specific atomic positions can be targeted when a novel method is developed rather than that achieved traditionally.Previous carbohydrate modifications have been investigated in terms of their effect on the physical and chemical properties of the samples. The principal focus for these properties will be on rheological measurements, owing to potential application in the commercial sector by our industrial partner. Other physical and chemical properties which are important to study include solubility, viscosity, molecular mobility, deposition and cleaning. Many of these properties could be measured during a placement period in our commercial partner's laboratories as well as on the University's NMR spectrometers.In addition to the effect that carbohydrate modification has on the physical and chemical properties of the resultant sample, effects are also evident in the ability of the carbohydrate to interact with other compounds that it may encounter. The effect that modifications have on these interactions will also be studied using several test systems for proteins, other carbohydrates and/or surfactant molecules. In certain cases, the study of interaction variability, using structural analysis methods, will be coupled with biological assays. Studying these interactions structurally will require the combination of NMR with other common methods, such as isothermal titration calorimetry and circular dichroism or differential scanning fluorimetry/calorimetry, to generate kinetics and protein stability data respectively when the modified polysaccharide is added.