Exploiting Selective Surface Activation for Surface Enhanced Spectroscopy Measurements

爱荷华州大学的这项研究得到了化学系化学理论、模型和计算方法项目的支持，该项目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）的效用。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。爱荷华州团队将寻求方法来了解两性离子表面配体电荷差异如何影响它们对金的亲和力。通过部分弱化表面稳定剂，在金属上产生小口袋用于随后的分子结合，包括传统上不容易与金结合的分子，从而增加了这种灵敏和特异性检测方法的分析实用性。研究团队将专注于专业发展和谁追求这项研究的学生的培训。为了帮助创造一个公平的环境，该小组将保持一个活的文件，总结沟通，道德，实验规划和文件，尊重和安全的期望。该小组还计划与K-12学生进行面对面和虚拟的外展活动，重点是化学以及纳米级物体和属性。这个爱荷华州大学的团队将通过利用分子间相互作用，溶剂化和分子-基底相互作用产生的化学效应来解决与Sers的可重复性和定量能力相关的挑战。调整金纳米星使用阳离子，质子，和溶剂的表面稳定的两性离子的结合亲和力，有利于形成疏水性的结合口袋上的金纳米星表面。通过局部调节表面配体中的电子密度，使用Sers和其他表面敏感检测方法探测这些活性位点的疏水性和尺寸。该小组随后调整分子溶解度和Sers激发条件，以量化和理解分子与金界面之间的化学相互作用。通过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理的理解，Sers和其他光谱技术的实用性将得以实现。该奖项反映了NSF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。

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.