Engineering cyanine aggregation and self-assembly to access exceptionally red-shifted organic chromophores

在这项由化学系高分子、超分子和纳米化学计划资助的项目中，加州大学洛杉矶分校化学系的Ellen M.Sletten教授和Justin R.Caram教授正在开发新的荧光化合物，这些化合物在电磁光谱的红外区重新发光。红外线通常是肉眼看不见的，但可以感觉到或探测到热量。与x射线类似，这种光可以穿透许多物体，包括皮肤和组织。这项研究中使用的化合物非常复杂，但很容易制成，具有独特的性质，使它们能够被高度着色。此外，当它们通过溶液中的分子相互作用组装时，它们的亮度要高出几个数量级。光的强度对于生物医学成像应用特别重要，例如人体内癌细胞的早期检测。此外，这项研究还与电信相关光学领域中新的令人兴奋的设备的开发有关，在这些领域中，信息使用红外光进行长距离通信。这项工作为本科生和研究生提供合成有机化学和分析表征技术方面的培训和教育。还开展了几项外联活动，其中包括对更广泛的社区进行有关荧光和电磁辐射的教育。这项研究是吸引少数族裔和社区大学生参与科学研究的一个很好的途径。这项研究集中于在电磁光谱的短波红外区域(SWIR，1000至2000 nm)发射的菁类荧光团的J-聚集体。为了创建SWIR J-聚集体，对促进发色团自组装成J-聚集体的因素进行了系统的研究。菁染料是理想的络合物，因为它们很容易合成，而且已知形成具有显著红移的J-聚集体。在项目的第一部分，通过系统的化学修饰和环境控制，探索了四种假想的控制J-聚集的现象(两亲性、反离子、多亚甲基链修饰和杂环极化率)。在第二个目标中，这些策略被扩展到一种已知的SWIR菁染料。这项研究有可能产生用于生物成像和电信应用的变革性新型纳米材料。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。

In this project funded by the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professors Ellen M. Sletten and Justin R. Caram of the Department of Chemistry at the University of California-Los Angeles are developing new fluorescent chemical compounds that re-emit light in the infrared region of the electromagnetic spectrum. Infrared waves are generally invisible to the human eye, but can be felt or detected as heat. Similar to x-rays, this light can penetrate through many objects, including skin and tissue. The compounds used in this research are very complex, yet easily made with unique properties that enable them to be highly colored. Additionally, they are several orders of magnitude brighter when assembled through molecular interactions in solution. The light intensity is particularly important for biomedical imaging applications such as early detection of cancer cells in human body. Additionally, the research is of relevance to the development of new and exciting devices in telecom-relevant optical fields in which information is communicated through long distances using infrared light. This work provides training and education to undergraduate and graduate students in synthetic organic chemistry and analytical characterization techniques. Several outreach activities are also developed that include educating the broader community about fluorescence and electromagnetic radiation. The research is an excellent avenue for engaging underrepresented minority and community college students in science.This research is focused on J-aggregates of cyanine fluorophores which emit in the shortwave infrared region of the electromagnetic spectrum (SWIR, 1000 to 2000 nm). To create SWIR J-aggregates, a systematic study of the factors that promote the self-assembly of chromophores into J-aggregates is conducted. Cyanine dyes are ideal complexes because they are easily synthetically accessible and are known to form J-aggregates with significant redshifts. In the first part of the project, four phenomena that are hypothesized to control J-aggregation (amphiphilicity, counterions, polymethine chain modification, and heterocycle polarizability) are explored through systematic chemical modifications and environmental control. In the second aim, these strategies are extended to a known SWIR cyanine dye. This research has the potential to generate transformative novel nanomaterials for applications in bioimaging and telecommunications.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.