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，他们正在开发这些材料，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。这些聚合物组织成几何形状，这些几何形状由水中的盐和酸浓度等因素决定。这些几何形状对聚合物发出的光的颜色和亮度都有很大影响。该项目使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。参与这项研究为研究生提供光学和聚合物科学方面的培训，以及与致力于具有医学意义的问题的国际合作者的互动。由于研究中的材料无毒，研究团队正在利用它们开发动手活动，作为罗切斯特大学为天才学生开设的暑期课程的一部分，并在罗切斯特博物馆和科学中心为普通公众举办展览。技术描述：研究团队正在测试由荧光共轭聚电解质组成的多个发色团中的能量转移如何控制其降解、荧光强度和光谱的模型。特别是，该小组正在调查生色团聚集导致荧光猝灭以及发射强度和光谱波动的情况。使用超分辨率成像和同步光谱学相结合的方法，对几乎不发光的发色团的漂白产生强烈荧光的假设进行了验证。正在开发一种利用光热检测来测量单链吸收的补充方法，以检验这些材料中荧光猝灭的“暗物质”假说。研究人员正在研究这些共轭聚电解质链在不同的盐和pH环境中以及在亲水和疏水表面吸附时的光谱和荧光动力学。该团队正在开发能量转移的计算模型，以指导聚合物形态的设计，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.