CAREER: Sub-NanoNewton Force Spectroscopy in Liquids with Dual-Frequency-Modulation AFM

本学院早期职业发展（Career）项目的研究目标是开发一种基于原子力显微镜（AFM）的纳米级结构快速力学表征方法。新方法将依赖于最近研究的控制方案概念，该方案使用两个自激振动信号来实现同时成像和三维力谱。本研究的重点是水下结构，分为计算和实验两个阶段。计算阶段包括在表征过程中对流体、AFM探针和样品进行连续原子模拟，而实验阶段包括将新硬件集成到现有显微镜中，开发控制软件，并对模拟中相同样品的方法进行调试。可交付成果包括描述基本组件、基本机制和控制方案的过程规范；建模和分析工具，通过硬件演示和验证，研究成果文档，工程学生教育，以及第一代大学预科学生的工程研究经验。如果成功，这项工作的结果将通过在其原生水环境中对一些最微妙的生物样品进行表征来扩大目前的AFM能力，并将导致对亚纳米机械性能的更系统，定量和快速评估。这将有助于纳米工程计划，如纳米加工和纳米制造，这取决于设计具有良好定义的机械性能的可控结构。原子力显微镜表征新生物材料的能力的增强也将有利于癌症研究、基因组学和细胞重建等生物和医学领域，这些领域的进步可以直接有助于提高人类的生活质量。工程专业的研究生和本科生以及大学预科学生将通过课堂教学和参与研究而受益。

The research objective of this Faculty Early Career Development (CAREER) project is to develop a method for rapid mechanical characterization of nanoscale structures, based on atomic force microscopy (AFM). The new method will rely on a recently researched controls scheme concept that uses two self-excited vibration signals to enable simultaneous imaging and 3-dimensional force spectroscopy. The work focuses on structures submerged in water and consists of a computational and an experimental phase. The computational phase includes continuum-atomistic simulation of the fluid, AFM probe and sample during characterization, while the experimental phase includes incorporation of new hardware into an existing microscope, development of controls software and commissioning of the method for the same samples as in the simulations. Deliverables include a process specification describing fundamental components, basic mechanisms and controls schemes; modeling and analysis tools, demonstration and validation via hardware, documentation of research results, engineering student education, and engineering research experiences for first-generation pre-college students.If successful, the results of this work will broaden current AFM capabilities by enabling characterization of some of the most delicate biological samples in their native aqueous environment, and will lead to a more systematic, quantitative, and rapid evaluation of sub-nanometer mechanical properties. This will contribute to nanoscale engineering initiatives, such as nanofabrication and nanomanufacturing, which depend on the design of controllable structures with well-defined mechanical properties. The enhancement of AFM to characterize new biomaterials will also be beneficial in biological and medical fields like cancer research, genomics and cell reconstruction, where advances could directly contribute to improving the quality of life of human beings. Graduate and undergraduate engineering students and pre-college students will benefit through classroom instruction and involvement in the research.