Looping Dynamics of Semiflexible Polymers

半柔性聚合物的循环动力学

• 批准号: 1006485
• 负责人: Brian Todd
• 金额: $ 36万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1006485&HistoricalAwards=false
• 关键词: Looping; Dynamics; Semiflexible; Polymers

ID: MPS/DMR/BMAT(7623) 1006485 PI: Todd, Brian ORG: Purdue UniversityTitle: Looping Dynamics of Semiflexible PolymersINTELLECTUAL MERIT: Intramolecular loops can form whenever a polymer chain contains more than one reactive site. The physics underlying this process is the diffusive transport of two distal polymer segments to a common location ("looping"). Most polymer theories predict that polymer looping reactions do not follow traditional kinetic models, but these predictions have not been fully tested experimentally. The goal of the proposed research is to characterize semiflexible polymer looping dynamics, using DNA as a model experimental system. In particular, the PI will test a recent theoretical prediction that semiflexible polymer looping is amenable to a simple description based on Kramers rate theory. This simple description would greatly facilitate predictions of looping kinetics in practical biopolymer design applications, such as the kinetically-determined processing of DNA nanoparticles for non-viral gene therapy. Two independent methods of measuring polymer looping rates are proposed. In the first, a fluorophore will be attached to one end of the polymer and a quencher to the other. Looping kinetics can then be determined from loop-mediated fluorophore quenching, measured via fluorescence correlation spectroscopy (FCS). The second method uses kinetic competition between looping and a second-order capping reaction. The proposed research will characterize semiflexible polymer looping, culminating in a model that details the influence of polymer structure on the looping rate. This deepens our understanding of segmental motion in semiflexible polymers and extends a widely used biopolymer model into applications involving looping.BROADER IMPACTS: A major goal of this project is to train students to think about how polymer physics can be used in interdisciplinary applications such as biomaterials design and molecular biology. The PI has recruited two talented graduate students into the laboratory, and it is expected that the laboratory will soon contain a mix of students at different levels. The PI is a mentor in the "Horizons Program" for at-risk students at Purdue and hopes to attract some of his mentees into his lab. He will also continue to recruit and retain underrepresented minorities through mentoring, lab tours, and programs supported by the College of Sciences at Purdue University. In the past, the PI was a director of a mentoring program in a 100% minority public middle school in East Cleveland, Ohio. He plans to continue outreach with middle school-aged students in West Lafayette, Indiana. The PI is currently developing an outreach laboratory designed to introduce concepts of "bottom-up" materials design to middle school-aged students. The idea is to challenge the students to design "co-polymer sequences" out of macroscopic magnetic and non-magnetic "monomers" that are capable of self-assembling into structures, such as loops, knots, and cubes. Modest funding is included in the budget to purchase the materials to make these demonstration kits. When not in use, the demonstration materials will be made available to K-12 teachers through the department's Physics Outreach Resource Room.

ID：MPS/DMR/BMAT（7623）1006485 主要研究者：托德，布赖恩ORG：Purdue UniversityTitle：半柔性聚合物的成环动力学智能优点：只要聚合物链含有一个以上的反应位点，就可以形成分子内环。 该过程的物理基础是两个远端聚合物片段扩散运输到共同位置（“成环”）。 大多数聚合物理论预测聚合物成环反应不遵循传统的动力学模型，但这些预测尚未得到充分的实验验证。 拟议的研究的目标是表征半柔性聚合物成环动力学，使用DNA作为模型实验系统。 特别是，PI将测试最近的理论预测，半柔性聚合物成环是服从于一个简单的描述的基础上Kramers速率理论。 这种简单的描述将极大地促进在实际的生物聚合物设计应用中的成环动力学的预测，例如用于非病毒基因治疗的DNA纳米颗粒的动力学确定的处理。 提出了两种测量聚合物成环速率的独立方法。 在第一种情况下，荧光团将连接到聚合物的一端，猝灭剂连接到另一端。 然后可以从环介导的荧光团淬灭确定成环动力学，通过荧光相关光谱法（FCS）测量。 第二种方法使用成环和二级封端反应之间的动力学竞争。 拟议的研究将半柔性聚合物成环的特点，最终在一个模型，详细的聚合物结构对成环率的影响。 这加深了我们对半柔性聚合物中链段运动的理解，并将广泛使用的生物聚合物模型扩展到涉及looping.BROADER IMPLEMENTARY的应用中：这个项目的主要目标是培养学生思考如何将聚合物物理学应用于生物材料设计和分子生物学等跨学科应用。PI已经招募了两名有才华的研究生进入实验室，预计实验室很快将包含不同水平的学生。 PI是普渡大学风险学生“视野计划”的导师，并希望吸引一些学生进入他的实验室。 他还将继续通过指导、实验室图尔斯之旅和普渡大学科学学院支持的项目来招募和留住代表性不足的少数民族。 过去，PI是俄亥俄州东克利夫兰一所100%少数民族公立中学的辅导项目主任。 他计划继续与印第安纳州西拉斐特的中学生进行接触。 PI目前正在开发一个外展实验室，旨在向中学生介绍“自下而上”的材料设计概念。 这个想法是挑战学生设计“共聚物序列”的宏观磁性和非磁性“单体”，能够自组装成结构，如环，结和立方体。预算中包括少量资金，用于购买制作这些演示工具包的材料。 当不使用时，演示材料将通过该部门的物理外展资源室提供给K-12教师。