Harnessing the Aggregation Behavior of Near-Infrared (NIR-II) Fluorophores via Supramolecular Nano-scaffolds

通过超分子纳米支架利用近红外 (NIR-II) 荧光团的聚集行为

• 批准号: 2203640
• 负责人: Davita Watkins
• 金额: $ 46.5万
• 依托单位: University of Mississippi
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203640&HistoricalAwards=false
• 关键词: Harnessing; Aggregation; Behavior; Near; Infrared

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Davita L. Watkins of the University of Mississippi is developing polymeric systems that can encapsulate biocompatible organic fluorophores for fluorescence imaging. Fluorophores are dyes that contain special carbon-carbon double bonds called pi-bonds. When these pi-bonds are irradiated with light of a certain wavelength, it enables the fluorophores to re-emit that light but with a different wavelength and much higher intensity. This unique characteristic makes them particularly useful for bioimaging applications. In this research, biocompatible amphiphilic polymers containing both water-loving (hydrophilic) and oil-loving (lipophilic) segments will first be prepared. Their amphiphilic properties resemble those of other artificial compounds such as soaps and detergents, or even naturally occurring lipoproteins. Synthesized polymers will then be assembled to create well-defined nanosized capsules which are capable to trap fluorophores. Various dynamic processes that will occur during polymer assembly and encapsulation will be studied using several spectroscopic techniques. Results associated with this research have the potential to advance the field of bioimaging and further understanding of optical properties of fluorophores in nanoconfined environments. This work is a multi-disciplinary study in which fundamental aspects of development will provide fertile ground for the training of early career scientists and offer design guidelines toward functional polymeric materials. Specific outreach endeavors will focus on research activities for transfer students and/or students having nontraditional academic paths as they make up a significant portion of the collegiate population in the state of Mississippi. The research will equip the next generation of scientists with the skills, collaborative spirit, and creativity to solve complex societal problems. A diverse scholastic population will also become more exposed to the emerging and dynamic area of fluorescence imaging, preparing them to contribute to an expanding STEM (science, technology, engineering and mathematics) workforce. This research will develop new approaches to biocompatible organic fluorophores for fluorescence imaging. Specific emphasis will be placed on developing linear-dendritic block copolymers and dye-polymer conjugates with optical properties in the second near-infrared window (NIR-II, 1000–1400 nm), which has emerged as a high-priority in recent years due to poor stability and biocompatibility of current agents. By employing amphiphilic substrates, the fundamental mechanism of self-assembly that results in well-defined, uniform nanostructures ideal for fluorescence imaging will be elucidated. From the point of view of macromolecular design, linear-dendritic block copolymers will be synthesized with hydrophobic blocks consisting of polyesters such as polylactides and polycaprolactones. Hydrophilic dendritic branches will be composed of polyamidoamines. NIR-II fluorescent dyes with aggregation-induced emissive molecular frameworks capable of self-assembling into monodisperse micellar structures will be strategically designed with thienothiadiazole and thienoselenadiazole units as the core acceptor structures. This research is cross-cutting with relevance to principles of organic and physical chemistry, and materials science. The work has the potential to contribute to bio-imaging development by providing a deeper understanding of unconventional related photophysical phenomena.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.

在化学系大分子、超分子和纳米化学项目的支持下，密西西比大学的达维塔·L·沃特金斯正在开发能够封装生物兼容的有机荧光团的聚合物系统，用于荧光成像。荧光团是一种含有特殊的碳-碳双键的染料，称为圆周率键。当这些pi键被特定波长的光照射时，它使荧光团能够重新发射该光，但波长不同，强度更高。这种独特的特性使它们在生物成像应用中特别有用。在这项研究中，首先将制备包含亲水(亲水)和亲油(亲油)链段的生物相容的两亲性聚合物。它们的两亲性类似于其他人工化合物，如肥皂和洗涤剂，甚至天然产生的脂蛋白。合成的聚合物随后将被组装成能够捕获荧光团的定义良好的纳米大小的胶囊。将使用几种光谱技术研究聚合物组装和封装过程中发生的各种动态过程。与这项研究相关的结果有可能推动生物成像领域的发展，并进一步了解纳米受限环境中荧光团的光学性质。这项工作是一项多学科的研究，其中发展的基本方面将为早期职业科学家的培训提供肥沃的土壤，并为功能聚合物材料提供设计指南。具体的外展工作将侧重于针对转学学生和/或非传统学术途径的学生的研究活动，因为他们在密西西比州的大学人口中占很大比例。这项研究将使下一代科学家具备解决复杂社会问题的技能、合作精神和创造力。多元化的学术人群也将更多地接触到新兴和动态的荧光成像领域，为他们为扩大STEM(科学、技术、工程和数学)劳动力做出贡献做好准备。这项研究将开发用于荧光成像的生物兼容有机荧光团的新方法。重点将放在开发在第二近红外窗口(NIR-II，1000-1400 nm)具有光学性能的线状-树枝状嵌段共聚物和染料-聚合物共轭化合物，由于现有试剂的稳定性和生物相容性较差，近年来这一窗口已成为优先事项。通过使用两亲性底物，自组装的基本机制将导致明确的，统一的纳米结构理想的荧光成像。从大分子设计的角度出发，用聚乳酸、聚己内酯等聚酯组成的疏水嵌段可合成线状-树枝状嵌段共聚物。亲水性树枝状支链将由聚酰胺胺组成。具有聚集诱导发射分子骨架、能够自组装成单分散胶束结构的NIR-II荧光染料将被战略性地设计为以噻二唑和噻二唑为核心受体结构。这项研究是与有机化学、物理化学和材料科学相关的交叉学科。这项工作通过提供对非常规相关光物理现象的更深入的理解，有可能为生物成像的发展做出贡献。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。