Collaborative Research: Synthetic mucins with tunable structures and programmable interfacial behavior

大多数人一听到粘液这个词就会畏缩，一想到粘稠的粘液就会反感，但他们可能没有意识到，粘液是自然界中发现的最有趣、最多样化的物质之一。每种动物都利用粘液来满足各种各样的需要。例如，普通的花园蜗牛分泌一种粘液促进运动，另一种粘液帮助它们粘在墙上，第三种粘液在背部，保护它免受环境威胁。尽管黏液在自然界中很普遍，但人们对其如何改变性质，使其成为粘合剂和润滑剂的了解甚少。如果这些特性可以被理解并在合成材料中重现，那么它的应用范围将从眼药水到医疗植入物的涂层。该项目支持基础研究，以了解合成黏液聚合物的润滑性和粘附性-人造材料，模仿天然黏液的结构和性质。通过了解聚合物长度、组成和添加剂（如钙盐）的存在对其润滑性和粘附性的影响，就有可能设计出模仿天然粘蛋白特性的有用的合成粘蛋白。这个项目将为学生提供重要的教育机会，让他们探索材料研究的奇迹，以及遍布我们世界的日常物品背后的迷人科学。综合外展活动的重点是吸引从高中到本科的学生，并扩大传统上代表性不足群体学生对STEM的参与。技术摘要：该合作项目旨在创建一类新的仿生聚合物-合成粘蛋白-模拟的结构，反过来，糖基化多肽的性质，是粘液的主要成分。该研究包括系统地调查合成粘蛋白结构与流变学、力学和摩擦学性能之间的关系。具体来说，这三个研究目标是研究(i)仅由糖基化单体单元组成的均聚物，（ii）含有糖基化单体和含硫醇单体的可形成链间交联的随机共聚物，以及（iii）含有糖基化单体、含硫醇单体和能够与表面形成特定相互作用的单体的三嵌段共聚物。除了开发新的合成方法和聚合协议来分别创造单体和聚合物外，纳米摩擦学方法和动力学蒙特卡罗模拟将被应用于测量和理解这些新材料的行为。该项目的更广泛影响旨在通过扩大传统上代表性不足的群体获得STEM的机会，促进STEM并创造具有STEM能力的劳动力。具体的更广泛的影响活动将是(i)高中生材料科学实习计划，（ii）纽约市立大学和宾夕法尼亚大学之间的学生交流，以及（iii）科学推广日的摊位，旨在告知公众材料科学研究对日常生活的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL ABSTRACTMost people cringe when they hear the word mucus, repulsed by the image of gooey slime, but what they may not realize is that mucus is one of the most interesting and diverse materials found in the natural world. Every animal uses mucus to fill a wide range of needs. The common garden snail, for example, secretes one type of mucus that facilitates locomotion, another that helps them stick to walls, and a third mucus, found on the back, that protects it from environmental threats. Despite its prevalence in the natural world, very little is understood about how mucus changes properties to behave, in one case, as an adhesive and, in another, as a lubricant. If these properties can be understood and reproduced in a synthetic material, it could have applications ranging from eye drops to coatings for medical implants. This project supports fundamental research to understand the lubricity and adhesion of synthetic mucin polymers – human-made materials that mimic the structures and properties of natural mucus. By understanding the effects of polymer length, composition, and the presence of additives, such as calcium salts, on the lubricity and adhesion, it would be possible to design useful synthetic mucins that mimic the properties of natural mucins. This project will provide significant educational opportunities for students to explore the wonders of materials research and the fascinating science behind everyday objects that populate our world. Integrated outreach activities are focused on engaging students from high school to undergraduate levels, and broadening participation in STEM amongst students from traditionally underrepresented groups.TECHNICAL ABSTRACTThis collaborative project aims to create a new class of biomimetic polymers – synthetic mucins – that emulate the structures and, in turn, the properties of the glycosylated polypeptides that are the primary components of mucus. The research involves investigating systematically the relationship between synthetic mucin structure and rheological, mechanical, and tribological properties. Specifically, the three research objectives are to study the properties of (i) homopolymers composed solely of glycosylated monomeric units, (ii) random copolymers containing glycosylated monomers and thiol-containing monomers that can form interchain cross-links, and (iii) triblock copolymers that contain glycosylated monomers, thiol-containing monomers, and monomers capable of forming specific interactions with surfaces. In addition to developing new synthetic methods and polymerization protocols to create the monomers and polymers, respectively, nanotribological methods and kinetic Monte Carlo simulations will be applied to measure and understand the behavior of these new materials. The broader impacts of this project are aimed to promote STEM and to create a STEM-capable workforce by expanding access to STEM opportunities to traditionally underrepresented groups. Specific broader impact activities will be (i) an internship program in materials science for high-school students, (ii) student exchanges between CUNY and the University of Pennsylvania, and (iii) booths at science outreach days intended to inform the public on the impact of materials science research on everyday life.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.