Giant Polymer Brushes: How Fluid-Like Hyaluronan Brushes Minimize Biofilm Adhesion

非技术摘要令人惊讶的是，通过改变表面的性质可以实现多少。当制成疏水性时，表面排斥水，并且可以例如保护纸张或木材免受水分侵入和损坏。当对特定气体或生物分子起反应时，它可以成为超灵敏的检测器，例如冠状病毒颗粒的生物传感器。一种非常成功的控制表面性质以产生如上所述的设计材料的方法是将聚合物以高密度锚在表面上，使得聚合物由于其相邻物的拥挤而排列并远离表面伸展。这种配置被称为聚合物刷。 聚合物刷已被用于各种令人惊叹的实际应用。这项拨款有双重科学目的。第一个目的是利用自然界的分子机器，通过直接从表面生长分子来生产聚合物刷。令人惊讶的是，这项新技术能够生产比传统技术厚近一百倍的聚合物刷层。这为材料的战略设计提供了令人兴奋的新特性。第二个目的是解决困扰人类的一个重要问题：生物膜的形成--也就是说，寄生细菌的群落在自己制造的粘液状粘稠物中根深蒂固并受到保护。 聚合物刷是延迟生物膜附着的流行策略，但最终，它们仍然失败。受到有希望的初步结果的激励，该项目在该资助中探索了巨大的分子机器产生的刷子及其相应的流体状界面是否可以导致细菌无法束缚的表面-这是一种最近才在其他环境中引入的新策略。为了确保任何仍然设法粘附的细菌都能被迅速消除，研究人员将在刷子的大体积内嵌入抗菌剂。总之，这些措施将导致一个令人兴奋的新聚合物刷技术的成熟，解决细菌感染和人造材料污染的古老问题。在推广和教育方面，柯蒂斯实验室将发布一系列关于这个跨学科项目的科学，生物材料和应用的简短有趣的卡通视频。这些视频将在You Tube频道上分享并广泛传播。主题将包括抗菌材料，生物膜，聚合物刷，和分子机器制造聚合物。聚合物刷是一种重要的工具，工程接口在各种应用，如药物输送，植入，催化，抗菌材料。 这项资助将专注于查明柯蒂斯实验室最近建立的非传统超厚聚合物刷的防污性能的起源和程度。由透明质酸合成酶涂覆的表面制成，酶衍生的刷子是有史以来最厚的，几乎有两个数量级。初步结果表明，这些透明质酸刷排斥细菌并防止生物膜粘附长达一周，表现比透明质酸膜好一个数量级，透明质酸膜被认为具有上级防污性能。Curtis实验室将测试这一假设，即这些刷子的上级性能来自其流体状界面，类似于最近为抗生物膜应用引入的其他非常成功的材料。 此外，他们将通过系统研究刷子接枝密度和分子量对刷子防污性能的依赖性来优化刷子的防污性能。最后，为了最大限度地提高刷子的抗生物膜性能，他们将在整个材料中添加杀菌剂，以创建具有最佳抗菌性能的多功能生物界面。更广泛地说，这项研究将有助于继续开发一类新的聚合物刷，预计将在材料科学中找到更广泛的应用。在推广和教育方面，柯蒂斯实验室将发布一系列关于该项目的科学，生物材料和应用的简短有趣的卡通视频。这些视频将在You Tube频道上分享并广泛传播。主题将包括防污材料，生物膜，聚合物刷等，此外，柯蒂斯博士将继续努力，通过利用这笔赠款建立联系，并与教师，顾问和学生建立持久的关系，在历史上黑人学院和大学增加干的多样性。这些活动的主要目标是：（1）建立有效的关系，以帮助改善少数民族学生的招聘和保留;（2）通过对话学习如何改善格鲁吉亚理工学院的氛围，使其对有色人种的学生更加欢迎和支持。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响进行评估，被认为值得支持审查标准。

Non-Technical AbstractIt is surprising how much can be accomplished by changing the properties of a surface. When made hydrophobic, a surface repels water and can, for example, protect paper or wood from moisture intrusion and damage. When made reactive to a specific gas or biomolecule, it can become an ultra-sensitive detector, for example a biosensor for coronavirus particles. One very successful way to control surface properties, so as to create designer materials like those described above, is to anchor polymers to the surface at such a high density that they align and stretch away from the surface because of crowding by their neighbors. This configuration is known as a polymer brush. Polymer brushes have been used in a stunning variety of practical applications. This grant has a twofold scientific purpose. The first purpose is to leverage nature’s molecular machines to produce polymer brushes by growing molecules directly from the surface. Amazingly, this new technology enables the production of polymer brush layers nearly one hundred times thicker than the those achievable with conventional techniques. This presents exciting new properties for the strategic design of materials. The second purpose is to address an important problem that plagues mankind: the formation of biofilms – that is communities of recalcitrant bacteria entrenched and protected in a mucous-like goo of their own making. Polymer brushes are a popular strategy to delay biofilm attachment but ultimately, they still fail. Motivated by promising preliminary results, the project explores in this grant whether the giant molecular-machine generated brush and its corresponding fluid-like interface can lead to a surface that the bacteria are unable to tether to – a new strategy only recently introduced in other contexts. To ensure that any bacteria which still manage to adhere are quickly eliminated, the researchers will embed antimicrobials within the large volume of the brush. Together, these measures will result in the maturation of an exciting new polymer brush technology addressing the age-old problem of bacterial infection and contamination of man-made materials. In outreach and education, the Curtis lab will publish a series of short playful cartoon videos about the science, biomaterials, and applications of this interdisciplinary project. The videos will be shared on a You Tube channel and disseminated widely. Topics will include anti-microbial materials, biofilms, polymer brushes, and molecular machines for making polymers. Technical AbstractPolymer brushes are an important tool for engineering interfaces in a variety of applications such as drug delivery, implants, catalysis, and anti-microbial materials. This grant will focus on pinpointing the origin and extent of the anti-fouling properties of a non-traditional, ultra-thick polymer brush recently established in the Curtis lab. Fabricated by surfaces coated with hyaluronan synthase, the enzyme-derived brushes are the thickest ever created by almost two orders of magnitude. Preliminary results demonstrate that these hyaluronan brushes repel bacteria and prevent biofilm adhesion for up to a week, performing an order of magnitude better than hyaluronan films, which are recognized as having superior anti-fouling properties. The Curtis lab will test the hypothesis that the superior performance of theses brushes arises from their fluid-like interface, similar to other recent very successful materials introduced for anti-biofilm applications. In addition, they will optimize the anti-fouling performance of the brushes with systematic studies of its dependence on brush grafting density and molecular weight. Lastly, to maximize the anti-biofilm properties of the brush, they will immobilize biocides throughout the material to create a multi-functional biointerface with optimal anti-microbial performance. More broadly, this research will contribute to the continued development of a new class of polymer brush, which is expected to find broader applications in materials science. In outreach and education, the Curtis lab will publish a series of short playful cartoon videos about the science, biomaterials, and applications of this project. The videos will be shared on a You Tube channel and disseminated widely. Topics will include anti-fouling materials, biofilms, polymer brushes, etc. Additionally, Dr. Curtis will continue her efforts to increase diversity in STEM by using the period of this grant to establish contacts and build lasting relationships with faculty, advisors, and students at historically Black colleges and universities. These activities have the primary goals of (1) building effective relationships to help improve recruitment and retention of minority students and (2) learning through conversations how to enhance the climate at Georgia Tech to make it more welcoming and supportive for students of color.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.