Nonlinear Optical Analysis of Molecular Composition and Dynamics within Heterogeneous Assemblies

在化学系化学测量和成像(CMI)计划的支持下，普渡大学的Garth Simpson教授正在开发一种新的成像工具，以绘制多相组件的化学成分和动力学图。了解具有高灵敏度和亚微米空间分辨率的化学复杂性对于了解治疗材料中化学成分的稳定性和生物利用度是重要的，而痕量物种的存在会影响二维材料的结晶和相变。辛普森教授和他的团队将开发一种基于红外光谱和分子手性的新成像工具，以绘制结构不均匀组装中的组成和翻译动力学图。他们的发现可能会带来从图像中提取化学信息的新方法，包括活性分子成分在药物中的分布情况。辛普森教授亦会主持一项有关非线性光学的短期课程，并让学生参与研究活动。透过整合手性光谱对比度及在样本中制造光漂白栅格，将加强光热红外成像在光谱指纹区的测量能力。这种方法有望通过提高时间和空间分辨率来解决传统红外成像中的扩散不均匀问题。通过使用手性特定的光谱，将使用数学框架来解释和预测微结构组件中的分子取向和顺序。在有序体系的中红外传输测量中预测的手性特定效应将扩展到微晶体和组织。最后，用于光漂白后荧光恢复的空间傅里叶变换方法将被用于构建多相组装内分子扩散系数的空间分辨图。这些局部粘度图有可能提供有关组成和分子传输如何管理生物活性物质行为的关键细节。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。

With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, Professor Garth Simpson of Purdue University is developing a new imaging tool to map the chemical composition of and dynamics in heterogeneous assemblies. Understanding chemical complexity with high sensitivity and sub-micrometer spatial resolution is important for understanding the stability and bioavailability of chemical components in therapeutic materials while the presence of trace species can influence crystallization and phase transformations in two dimensional materials. Professor Simpson and his group will develop a new imaging tool based on infrared spectroscopy and molecular chirality to map the composition and translational dynamics within structurally heterogeneous assemblies. Their discoveries could lead to new approaches for extracting chemical information from images including how active molecular components are distributed in pharmaceuticals. Professor Simpson will also lead a short course on nonlinear optics and engage students in research activities.The measurement capabilities of photothermal infrared imaging will be enhanced in the fingerprinting region of the spectrum through integration of chiral spectroscopic contrast and the creation of photobleached gratings in samples. This approach is expected to resolve inhomogeneities of diffusion in traditional infrared imaging by improving both temporal and spatial resolution. By using chiral-specific spectroscopies, molecular orientation and order within microstructured assemblies will be interpreted and predicted using a mathematical framework. Chiral-specific effects predicted in the mid-infrared transmission measurements of ordered systems will then be extended to microcrystals and tissues. Finally, a spatial Fourier transform approach for fluorescence recovery after photobleaching will be used for construction of spatially-resolved maps of molecular diffusivity within heterogeneous assemblies. These local-viscosity maps have the potential to provide key details about how composition and molecular transport govern the behavior of biologically-active materials.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.