CAREER: Design and Characterization of Aptamer-Amphiphiles for Selective Binding

职业：用于选择性结合的适体双亲物的设计和表征

• 批准号: 0846274
• 负责人: Efrosini Kokkoli
• 金额: $ 40万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0846274&HistoricalAwards=false
• 关键词: CAREER; Design; Characterization; Aptamer; Amphiphiles

0846274KokkoliIntellectual Merit: Aptamers are short single-stranded oligonucleotides. They are chemically produced, have the capability of binding with high affinity and specificity a variety of different targets, and have been shown to be useful as therapeutic agents and diagnostic tools. Their affinities are often comparable to those observed for monoclonal antibodies, and are significantly higher compared to those of peptides. As aptamer-amphiphiles, aptamers attached to a hydrophobic tail, they can assemble with other amphiphilic molecules into a variety of different structures. Their assembly with lipids to form aptamer-functionalized liposomes will be desirable in biotechnological applications, such as, targeted drug delivery. The PI proposes to study aptamers as aptamer-amphiphiles and, in particular, aptamer sequences that bind fractalkine (an adhesion molecule expressed only at sites of infection or inflammation, such as cancer), and hypothesizes that the orientation of the aptamer headgroup, and the use of a spacer between the hydrophobic tail and the headgroup, will affect the assembly behavior of the molecule, and the secondary structure of the aptamer, thus subsequently affecting its binding affinity for its target. To test this hypothesis the following research tasks have been set: In Research Task 1, the goal is to test the biological affinity of the designed aptamer-amphiphiles, free in solution, and incorporated in liposomes, thus evaluating which designs bind to fractalkine. The PI will characterize the aptamer-amphiphiles in Research Task 2 with different techniques (CD, melting curves, cryo-TEM, SAXS, and SANS) that will evaluate the secondary structure of the aptamer, and assembly behavior of the amphiphiles. These results will enable a connection between the biological function of aptamer-amphiphiles with their structure and corresponding phase behavior. This research will advance knowledge and understanding as it will not only furnish favorable amphiphilic properties (headgroup orientation, spacer design, secondary structure, assembly behavior) for the design of aptamer-amphiphiles, but will provide a fundamental understanding of why these properties are beneficial. Broader Impact: -Technical Impact. The PI proposes the design and characterization of a novel tool, "aptamer-amphiphiles", based on the expectation that by changing their structural segments one can control their morphology, surface chemistry, and function. A comprehensive characterization of secondary structure, amphiphilic and self-assembly properties, and the link between these properties and the engineering of targeted delivery vehicles is proposed here for the first time. The research activities represent transformative research as they may lead to the genesis of a new field of research on "aptamer-amphiphiles" (a new term in the literature) that will merge rational amphiphile design principles, chemistry, biology, and engineering in order to provide advanced systems for targeted drug delivery. -Societal / Educational Impact. Fractalkine is an attractive new target for the development of anti-angiogenesis and anti-cancer agents. By choosing aptamers that bind to fractalkine as the model system, the proposed work outlines a logical approach that can be applied to the future design of aptamer-amphiphiles that can functionalize nanoparticles and increase the particle's specificity and affinity for fractalkine, thus having great therapeutic potential and significantly benefiting society. The educational plan is strongly integrated with the research plan. The PI is collaborating with "DragonflyTV" (a science series that presents middle school students doing real science, supported by NSF and produced by Twin Cities Public Television (TPT), and seen on Public Broadcasting Service (PBS) stations nationwide) with the goal of enhancing scientific and technological understanding among children and adults. Furthermore, the PI has participated, and continue to participate, in outreach activities organized by TPT with the goal of attracting women in sciences and engineering (a long term goal for the PI), and is currently collaborating, and will continue to do so in the future, with MRSEC. Through MRSEC the PI will be hosting during the summer high school teachers, and minority undergraduates from a nationwide pool of applicants, through a well established network of high schools, and minority undergraduates from a number of Minority Serving Institutions.

0846274 Kokkoli智力优点：适体是短的单链寡核苷酸。它们是化学产生的，具有以高亲和力和特异性结合多种不同靶标的能力，并且已显示可用作治疗剂和诊断工具。它们的亲和力通常与单克隆抗体所观察到的亲和力相当，并且与肽的亲和力相比显著更高。作为适体-两亲分子，适体连接到疏水尾部，它们可以与其他两亲分子组装成各种不同的结构。它们与脂质组装以形成适体官能化的脂质体在生物技术应用中是期望的，例如靶向药物递送。PI建议将适体作为适体-两亲物进行研究，特别是结合Fractalkine的适体序列（仅在感染或炎症部位表达的粘附分子，如癌症），并假设适体头基的方向，以及疏水尾和头基之间间隔区的使用，将影响分子的组装行为，以及适体的二级结构，从而随后影响其与靶的结合亲和力。为了检验这一假设，已经设定了以下研究任务：在研究任务1中，目标是测试所设计的适体-两亲物的生物亲和力，游离于溶液中，并掺入脂质体中，从而评估哪些设计与fractalkine结合。PI将采用不同的技术（CD、熔解曲线、cryo-TEM、SAXS和SANS）表征研究任务2中的适体-两亲物，这些技术将评价适体的二级结构和两亲物的组装行为。这些结果将使适体-两亲物的生物功能与它们的结构和相应的相行为之间的联系。这项研究将推进知识和理解，因为它不仅将为适配体-两亲物的设计提供有利的两亲性（头基取向，间隔设计，二级结构，组装行为），而且将提供为什么这些特性是有益的基本理解。 更广泛的影响：技术影响。PI提出了一种新型工具“适体-两亲物”的设计和表征，其基于通过改变其结构片段可以控制其形态、表面化学和功能的期望。本文首次提出了一个全面的表征二级结构，两亲性和自组装性能，以及这些性能与靶向运载工具工程之间的联系。这些研究活动代表了变革性的研究，因为它们可能导致一个新的研究领域的起源“适体-两亲物”（文献中的一个新术语），该领域将合并合理的两亲物设计原理，化学，生物学和工程学，以提供先进的靶向药物递送系统。社会/教育影响。Fractalkine是一个有吸引力的新靶点，用于开发抗血管生成和抗癌药物。 通过选择与fractalkine结合的适体作为模型系统，所提出的工作概述了一种逻辑方法，该方法可应用于未来设计适体-两亲物，该适体-两亲物可使纳米颗粒功能化并增加颗粒对fractalkine的特异性和亲和力，从而具有巨大的治疗潜力并显着造福社会。教育计划与研究计划紧密结合。PI正在与“DragonflyTV”（一个科学系列节目，介绍中学生做真实的科学，由国家科学基金会支持，双城公共电视台制作，在全国公共广播服务电台播出）合作，目的是提高儿童和成人对科学和技术的理解。 此外，PI已经并将继续参加TPT组织的外联活动，目的是吸引科学和工程领域的妇女（PI的长期目标），目前正在与MRSEC合作，今后将继续这样做。通过MRSEC，PI将在夏季接待高中教师，并通过完善的高中网络从全国范围内的申请人中挑选少数民族本科生，以及来自一些少数民族服务机构的少数民族本科生。