A new bio-based nanomaterial: Fundamental understanding of xylan single crystals for functional applications

世界人口预计将在未来十几年内增加10亿人，这些人将需要食物和能源，以及能够在不填埋或丢弃世界海洋的情况下返回地球的材料。对于后者，我们可以将来自农业秸秆、木纤维和其他植物生物质的资源用于许多创新应用。然而，实际情况是，植物中的成分极其复杂，使得它们很难工业化使用，因为大自然利用复杂的生物聚合物来实现生物材料的特性和所需的特性。在我们的研究计划中，我们用专门的加工方法提取生物聚合物，以限制材料的固有变异性，并对结构和由此产生的特性进行表征，以便将它们转化为有用的、重要的、统一的材料。以前的材料例子包括用于超级电容器应用的碳气凝胶、用于油/水分离的柔性木质素海绵以及用于疏水涂层的简单木素酯。在最近的DG时期的支持下，我们通过简单的热处理从亲水性可控的水溶液中纺制出多糖纳米纤维。此外，冷冻电子显微镜显示，我们能够分离杂多糖并将其转化为单晶纳米颗粒。我们还意外地发现，木聚糖可以在界面上结晶。在这项提议中，我们扩展了将复杂的杂多糖从植物资源转化为尺寸和表面化学可控的均质纳米颗粒的概念。我们将利用合成化学中开发的单晶方法来帮助获得定义尺寸的木聚糖晶体。我们还将利用界面结晶的能力来建立二维膜，并研究在潜在的可食用涂层上形成超稳定乳液的方法，以延长食品的保质期。木聚糖纳米颗粒将被表面功能化，以形成化合物，可以将银盐还原为纳米颗粒或吸附金纳米颗粒，这些纳米颗粒将能够作为表面增强拉曼光谱衬底，用于化学和生物传感的诊断。该项目中的“我们”代表了有才华、有好奇心的学生和博士后研究员，他们产生了重大发现，并为研究项目共同努力。拟议的研究将为出色的培训提供机会，受训人员将成为木质纤维素生物质结构和加工方面的专家，使他们掌握分析技能，包括光谱分析、热分析和先进的纳米成像方法。集团拥有优秀的设备资源，2名博士生和10名本科生将通过这笔赠款做好准备，在以可持续发展方法和绿色化学为基础的重要纳米技术领域拥有杰出的职业生涯。

The world's population is expected to increase by a billion people in the next dozen years and these people will need food and energy, along with materials that can be returned to the earth without landfilling or littering the world's oceans. For the latter, we can use resources from agricultural straw, wood fibre, and other plant biomass for many innovative applications. However, the practicality is that the components within the plants are extremely complex, making them hard to use industrially, as nature utilizes complex biopolymers to achieve properties and desired traits of biological materials. In our research program, we extract biopolymers with specialized processing methods that limit the inherent variability of the material and we characterize the structure and resulting properties in order to transform them into useful, and importantly, uniform, materials. Previous examples of materials include carbon aerogels for supercapacitor applications, flexible lignin sponges for oil/water separation, and simple lignin esters for hydrophobic coatings. Supported in the most recent DG period, we created polysaccharide nanofibres spun from water solutions with controlled hydrophilicity by simple thermal treatment. In addition, we were able to isolate heteropolysaccharides and transform them into single crystal nanoparticles, revealed by cryo-electron microscopy. We also unexpectedly found that xylan could crystallize at interfaces. In this proposal, we are expanding the concept of conversion of complicated hetero-polysaccharides from plant resources into homogeneous nanoparticles of controlled size and surface chemistry. We will utilize the single-crystal methods developed in synthetic chemistry to help achieve xylan crystals of defined dimensions. We will also exploit the ability to crystallize at interfaces to establish two-dimensional membranes and investigate methods to form ultra-stable emulsions to potential edible coatings to extend the shelf life of foods. The xylan nanoparticles will be surface functionalized to form compounds that can reduce silver salts into nanoparticles or adsorb gold nanoparticles that would be able to serve as surface enhanced Raman spectroscopy substrates for diagnostics for chemical and biological sensing. The "we" in the program represents the talented and curious students and post-doctoral fellows that generate significant findings and work together for the research program. The proposed research will provide opportunity for outstanding training where trainees will become experts in lignocellulose biomass structure and processing, giving them analytical skills that includes spectroscopy, thermal analysis, and advanced nanoscale imaging methods. With outstanding equipment resources in the group, 2 PhD students and 10 undergraduate students supported will be well prepared by this grant to have outstanding careers in important nanotechnology field anchored by sustainable approaches and green chemistry.