Photophysics and Stability of Multichromophoric Polyelectrolytes

非技术描述：研究小组研究了一类能够发光的水溶性聚合物。这些材料正在与化学家合作研究，化学家正在开发它们用于肿瘤的生物医学成像，以及用于检测具有医学意义的蛋白质和DNA序列。这些聚合物组织成由诸如水中的盐作为盐和酸浓度等因素决定的几何形状。这些几何形状强烈影响聚合物发出的光的颜色和亮度。该项目采用单个聚合物链的显微镜来研究聚合物构象和溶液条件如何影响发射光的强度和稳定性。参与研究为光学和聚合物科学的研究生提供培训，以及与国际合作者就具有医学意义的问题进行互动。由于正在研究的材料是无毒的，研究小组正在使用它们来开发实践活动，作为罗切斯特大学为天才学生开设的夏季课程的一部分，并在罗切斯特博物馆和科学中心为公众举办展览。技术描述：该研究小组正在测试多个能量转移模型，包含荧光共轭聚电解质的发色团集合控制它们的降解、荧光强度和光谱。特别是，该小组正在研究发色团聚集导致荧光猝灭以及发射强度和光谱波动的情况。强烈的荧光来自几乎不发光的发色团的漂白的假设正在使用超分辨率成像与同步光谱相结合进行测试。正在开发一种使用光热检测来测量单链吸收的补充方法，以测试这些材料中荧光猝灭的“暗物质”假设。研究人员正在研究这些共轭双链在不同盐和pH环境中的光谱和荧光动力学，以及吸附在亲水和疏水表面时的光谱和荧光动力学。该团队正在开发用于指导聚合物形态设计的能量转移计算模型，以提高成像应用的荧光效率和稳定性。

Nontechnical description: The research team studies a class of water-soluble polymers that are capable of light emission. The materials are being studied in collaboration with chemists who are developing them for biomedical imaging of tumors, and for applications to detection of proteins and DNA sequences of medical interest. These polymers organize into geometries that are determined by factors such as salt and acid concentrations in the water. Those geometries strongly influence both the color and brightness of the light emitted from the polymers. The project employs microscopy of single polymer strands to investigate how the polymer conformation and solution conditions affect the intensity and stability of the emitted light. Participation in the research provides training for graduate students in optics and polymer science, as well as interactions with international collaborators working on problems with medical significance. Since the materials under study are non-toxic, the research team is using them to develop hands-on activities as part of a summer course at the University of Rochester for gifted students, and for exhibitions for the general public at the Rochester Museum and Science Center.Technical description: The research team is testing models of how energy transfer in multi-chromophore ensembles comprising fluorescent conjugated polyelectrolytes controls their degradation, fluorescence intensity, and spectrum. In particular, the group is investigating the circumstances under which chromophore aggregation leads to fluorescence quenching and fluctuations in the emission intensity and spectrum. The hypothesis that intense fluorescence arises from bleaching of nearly non-emissive chromophores is being tested using superresolution imaging combined with simultaneous spectroscopy. A complementary approach to measure the absorption of single chains using photothermal detection is being developed to test the "dark matter" hypothesis for fluorescence quenching in these materials. The researchers are studying the spectroscopy and fluorescence dynamics for these conjugated polyelectrolyte chains in different salt and pH environments, as well as when adsorbed on hydrophilic and hydrophobic surfaces. The team is developing computational models of energy transfer for guiding the design of polymer morphology, to improve fluorescence efficiency and stability for imaging applications.