Exploiting Selective Surface Activation for Surface Enhanced Spectroscopy Measurements

爱荷华大学的这项研究得到了化学系化学理论、模型和计算方法计划颁发的奖项的支持，该奖项旨在利用非共价分子间和分子-表面相互作用来扩大直接吸附到金纳米星上的分子的表面增强拉曼散射(SERS)的用途。SERS是一种强大的检测方法，它依赖于金属纳米颗粒的光学性质和分子-表面相互作用产生的化学效应。爱荷华州的研究小组将寻求方法来了解两性离子表面配体的电荷差异如何影响它们对黄金的亲和力。通过部分削弱表面稳定剂，在金属上产生小口袋以用于后续的分子结合，包括传统上不容易与金结合的分子，从而增加了这一灵敏而特异的检测方法的分析用途。研究团队将专注于从事这项研究的学生的专业发展和培训。为了帮助创造一个公平的环境，该小组将维护一份活的文件，其中总结了对沟通、道德、实验计划和文档、尊重和安全的期望。该小组还计划与K-12学生进行面对面的拓展活动，这些活动主要集中在化学以及纳米物体和属性上。这个爱荷华大学的团队将通过利用分子间相互作用、溶剂化和分子-底物相互作用产生的化学效应的作用，解决与SERS的可重复性和量化能力相关的挑战。使用阳离子、质子和溶剂调节表面稳定的两性离子在金纳米星上的结合亲和力，有助于在金纳米星表面形成疏水结合袋。通过局部调节表面配体中的电子密度，利用表面增强拉曼光谱和其他表面敏感检测方法来探测这些活性中心的疏水性和尺寸。该小组随后调整了分子的溶解度和SERS激发条件，以量化和了解分子与金界面之间的化学作用。通过发展对表面稳定剂中的电子分布如何影响分子-金属化学相互作用的机械理解，将实现SERS和其他光谱技术的实用性。该奖项反映了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。

This research at the University of Iowa is supported by an award from the Chemical Theory, Models and Computational Methods Program in the Division of Chemistry to exploit non-covalent intermolecular and molecule-surface interactions to expand the utility of surface-enhanced Raman scattering (SERS) of molecules that directly adsorb to gold nanostars. SERS is a powerful detection method that depends on the optical properties of metal nanoparticles and chemical effects arising from molecule-surface interactions. The Iowa team will pursue methods to understand how zwitterionic surface ligand charge differences influence their affinity to gold. By partially weakening the surface stabilizing agents, small pockets are generated on the metal for subsequent molecular binding, including molecules that do not traditionally bind readily to gold thus increasing the analytical utility of this sensitive and specific detection method. The research team will focus on the professional development and training of students who pursue this research. To aid in generating an equitable environment, the group will maintain a living document that summarizes expectations for communication, ethics, experiment planning and documentation, respect, and safety. The group also plans to perform outreach activities with K-12 students in person and virtually that focus on chemistry as well as on nanoscale objects and properties.This University of Iowa team will address challenges associated with the reproducible and quantitative capabilities of SERS by exploiting the roles of intermolecular interactions, solvation, and chemical effects arising from molecule-substrate interactions. Tuning the binding affinity of surface-stabilizing zwitterions on gold nanostars using cations, protons, and solvent facilitates the formation of hydrophobic binding pockets on gold nanostar surfaces. By locally modulating the electron density in the surface ligands, the hydrophobicity and dimensions of these active sites are probed using SERS and other surface sensitive detection methods. The group subsequently tunes molecular solubility and SERS excitation conditions to quantify and understand the chemical interactions between molecules and the gold interface. By developing a mechanistic understanding of how electron distribution in surface stabilizing agents impact molecule-metal chemical interactions, the utility of SERS and other spectroscopic techniques will be achieved.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.