CAREER: Molecular Basis for Viscoelastic Response on Nano-Mechanical Biosensors

该学院早期发展（CAREER）计划研究的目标是提供对在水性环境中操作的MEMS/NEMS谐振器中管理能量耗散的基本机制的理解，以实现高灵敏度生物传感器的设计。这种有前途的传感器技术目前受到缺乏理论框架的限制，该理论框架将共振频率的变化与结合到表面的特定靶分子联系起来。基于分子动力学技术的大规模原子模拟将被用来解决这个问题。具体来说，分子事件和内部动力学在固液界面将被表征，以了解纳米尺度的结构如何影响粘弹性。环境条件的影响，例如，温度和离子强度对能量耗散的影响将被表征和量化。共振频率的变化将被确定为离子的分子类型、长度和密度分布的函数。将建立导致界面处真实或表观滑移的条件。与一个实验小组密切合作将使模型所作的预测得到验证，并将确保科学发现的迅速传播。该项目的成果将是建立固/液界面的分子结构与谐振器的机械响应之间的关系。预测相对共振位移的能力将使能够设计能够实时生物传感的结构，并将导致对磨损和相关问题的基本理解。该补助金的教育部分包括对就读于PI正在开发的课程的本科生和研究生进行跨学科培训。奈米生物力学概念的电脑产生示范将被用作讲课范例。这项研究的科学成果将通过原子尺度摩擦研究和教学协同中心（AFRESH）传播，AFRESH是一个由NSF资助的多机构虚拟组织，汇集了纳米摩擦学领域的研究人员和教育工作者。此外，PI将与社会科学家合作，为可能对纳米生物技术发展存在偏见的公众创建一个外展计划。通过圆桌会议和小组讨论，将创造一个非敌对的环境，鼓励具有不同意识形态背景的参与者之间进行科学对话。

The objective of this Faculty Early Development (CAREER) Program research is to provide understanding of fundamental mechanisms that govern energy dissipation in MEMS/NEMS resonators operating in aqueous environments to enable design of highly sensitive biosensors. This promising sensor techonology is currently limited by lack of theoretical framework that relates the change in resonance frequency to a specific target molecule binding to a surface. Large scale atomistic simulations based on the molecular dynamics technique will be employed to address this issue. Specifically, molecular events and internal dynamics at the solid-liquid interface will be characterized to understand how the nanometer-scale structure impacts viscoelastic properties. The effect of environmental conditions, e.g., temperature and ionic strength, on energy dissipation will be characterized and quantified. Changes in resonance frequencies will be determined as a function of the molecule type, length, and density distribution of ions. Conditions that lead to true or apparent slip at the interface will be established. A close collaboration with an experimental group will allow for validation of predictions made by the models and will ensure a quick dissemination of scientific findings. The outcome of this project will be establishing of relationships between molecular structures at the solid/liquid interface and the mechanical response of resonators. The ability to predict relative resonance shifts will enable design of structures capable of real-time biosensing and will lead to basic understanding of wear and related issues. The educational component of this grant includes interdisciplinary training of undergraduate and graduate students enrolled in courses that are being developed by the PI. Computer-generated demonstrations of concepts in nano-biomechanics will be used as lecture examples. Scientific findings of this research will be disseminated through the Atomic scale Friction Research and Teaching Synergy Hub (AFRESH), which is an NSF-funded multi-institutional virtual organization that brings together researchers and educators in the field of nanotribology. Additionally, the PI will collaborate with social scientists to create an outreach program to the general public who may have some preexisting biases against developments in nano-biotechnology. Through round-table and panel discussions a non-hostile environment will be created in which a dialogue about science is encouraged among participants with diverse ideological backgrounds.