Predicting and Controlling the Coupling Between Dyes and Plasmonic Nanoparticles

在化学系化学测量和成像项目的支持下，密歇根大学的Biteen教授正在开发一种显微镜，以超高分辨率（纳米尺度）测量活细胞中生物分子的位置和运动。这种超分辨率显微镜结合了新兴的高分辨率显微镜技术和金属纳米颗粒的独特性质，金属纳米颗粒强烈影响附近染料分子的荧光发射。Biteen教授致力于使用高灵敏度显微镜来了解金属纳米颗粒与染料分子之间的相互作用，并控制耦合发射。她正在研究一种实时、无扰动、生物相容性的活细胞成像显微镜。比廷教授与女本科生和其他代表性不足的少数群体的学生密切合作。她通过支持公开讲座和为中学女生开发动手演示，向广大观众宣传科学是一个令人兴奋的领域。单分子超分辨率显微镜可以直接研究远低于半微米衍射极限的物理和光学效应，但由于探针相对于背景的亮度有限，特别是在细胞样品中，这种技术在实际应用中受到限制。等离子体纳米粒子（NPs）很容易产生超过100倍的场强增强来照亮近端染料，但由于传统实验方法的限制，改性染料发射也会产生定位偏差，这种偏差尚未得到充分表征。Biteen教授正在用NP等离子体提高单分子成像的分辨率。最先进的染料与金属NPs耦合的单分子荧光实验可以直接测量等离子体NPs对近端染料的影响。因此，单分子读数可以为染料- np相互作用的模型提供信息，同时，等离子体增强可以提高单分子荧光亮度。Biteen教授正致力于高精度、纳米级、等离子体增强的超分辨率显微镜：(1)测量等离子体NP产生的染料分子强度、光谱、方向和发射极化的变化；(2)根据目标1确定的关系，通过调节激发极化和频率来控制染料-NP耦合；(3)超分辨等离子体表面制备的活细胞中膜蛋白的位置和运动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Biteen at the University of Michigan is developing a microscope to measure position and motion of biomolecules in living cells with a super high resolution (at the nanometer scale). This super-resolution microscope combines emerging high-resolution microscopy techniques and the unique properties metal nanoparticles where metal nanoparticles strongly affect the fluorescence emission from nearby dye molecules. Professor Biteen works on using the high-sensitivity microscopy to understand the interaction between metal nanoparticles and the dye molecules and to control coupled emission. She is working toward a real-time, non-perturbative, biocompatible microscope for live-cell imaging. Professor Biteen works closely with undergraduate women students and students from other under-represented minority groups. She is promoting science as an exciting field to a broad audience by supporting public lectures and developing hands-on demos for middle school girls.Single-molecule, super-resolution microscopy enables direct investigations of physical and optical effects far below the half-micron diffraction limit of light, but this technique is restricted in practical applications by the limited brightness of probes relative to the background, especially in cellular samples. Plasmonic nanoparticles (NPs) readily produce over hundred-fold field intensity enhancements to brighten proximal dyes, but the modified dye emission also yields localization biases that have not yet been fully characterized due to the limitations of conventional experimental approaches. Professor Biteen is improving the resolution of single-molecule imaging with NP plasmonics. State-of-the-art single-molecule fluorescence experiments on dyes coupled to metal NPs can directly measure the effects of plasmonic NPs on proximal dyes. Therefore, the single-molecule readout can inform models of dye-NP interactions, while at the same time, plasmonic enhancement can improve the single-molecule fluorescence brightness. Professor Biteen is working toward high-accuracy, nanometer-scale, plasmon-enhanced super-resolution microscopy by: (1) measuring the changes in dye molecule intensity, spectrum, direction, and polarization of emission produced by a plasmonic NP, (2) controlling the dye-NP coupling by tuning the excitation polarization and frequency according to the relationships determined in objective 1, and (3) super-resolving the positions and movements of membrane proteins in living cells prepared on plasmonic surfaces.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.