EAGER: Nanoelectromechanical system for in situ measurement of cell surface charge

目的：本提案的目的是开发一种能够原位和按需检测单个细胞表面电荷的系统。为了实现这一目标，我们将制造一个尖端电荷量可控的机械系统。在与电池静电相互作用时，结构将以与电池表面电荷成正比的方式偏转。由于相互作用可能有其他成分，如范德华力和水合力，这些影响将通过改变悬臂上的电荷量来解除卷积，因此只测量静电相互作用。PI将调查一些癌细胞系表面电荷密度的程度，并将结果与正常细胞进行比较。他还将使用相同的机电系统对单个电池进行称重，并研究表面电荷和质量密度之间的关系。智力价值：长期以来，对细胞电学性质的研究一直很重要。最近的研究表明，癌症研究人员对表型与电学特性之间的关系越来越感兴趣。在这里，PI提出了一个系统，该系统可以在显微镜下查询用户根据需要识别的特定细胞。此外，该系统可用于悬停在固定在表面上的一组细胞上，或询问较大组织样本的一部分。该系统的多功能性也允许它作为一个质量传感器。因此，可以用微型镊子抓住细胞的电性能，并将其放置在机电系统的尖端进行按需称重，从而使电性能与质量密度相关联。更广泛的影响：细胞的胞内细胞器中包含大量的信息，这些信息编码在细胞表面膜和细胞周围结构上表达的基因产物。几个世纪以来，膜和膜表面吸引了许多科学家的注意。细胞表面膜参与了细胞与环境的各种相互作用，这些相互作用对健康和疾病具有相当大的意义。这里提出的系统不仅在研究各种细胞的电表面特性方面非常有用，而且在各种条件下进行这些研究也非常有用。如果成功，该项目将通过对特定细胞的原位电分析，对癌症研究产生广泛的影响。PI将从少数民族学生中挑选他的博士生。Savran教授为工科学生讲授系统和测量相关课程。他经常将跨学科的例子整合到传统的课程中。本研究的结果也将与本科生分享，并在课堂、作业和项目中作为例子。

Objective: The objective of this proposal is to develop a system that can perform in situ and on demand detection of surface charge of single cells. To achieve this objective we will fabricate ananomechanical system with a controlled amount of charge at its tip. Upon an electrostatic interaction with a cell, the structure will deflect in a manner that is proportional to the surface charge of the cell. Since the interaction could potentially have other constituents such as Van der Waals and hydration forces, these effects will be deconvoluted by varying the amount of charge on the cantilever, and hence only measuring the electrostatic interactions. The PI will investigate the extent of surface charge density on a number of cancer cell lines and compare the results with normal cells. He will also weigh the individual cells using the same electromechanical system and investigate the correlation between surface charge and mass density.Intellectual Merit: Investigation of electrical properties of cells has been important for a long time. Recent studies show that cancer researchers are increasingly interested in correlating phenotype with electrical properties. Here the PI proposes a system that can interrogate a particular cell identified by the user on demand under the microscope. In addition, the system can be used to hover above a group of cells immobilized on a surface or interrogate a section of a larger tissue sample. The versatility of the system also allows it to serve as a mass sensor. Hence, the cells interrogated for their electrical properties can be grabbed by a micro-tweezer and placed on the tip of the electromechanical system for on demand weighing, allowing correlation of electrical properties with mass density.Broader Impacts: Cells have an enormous amount of information packed within their intracellular organelles that code for the gene products expressed on the cell surface membrane and the structures in the cell periphery. Membranes and membrane surfaces have attracted the attention of many scientists for centuries. The cell surface membrane is involved in a wide variety of interactions of the cell with its environment, which are of considerable interest in health and disease. The system proposed here can be extremely useful not only in studying electrical surface properties of a wide variety of cells but also performing these studies under a wide range of conditions. If successful, the project could make a broad impact in cancer research by in situ electrical analysis of particular cells. The PI will choose his PhD student from a minority student body. Prof. Savran teaches courses related to systems and measurements to engineering students. He frequently integrates interdisciplinary examples into an otherwise traditional curriculum. The findings of this study will also be shared with undergraduate students and used as examples in class, in homework and projects.