Plasmonic mapping of ion channel activities in single cells

描述（由申请人提供）：研究和监测单细胞的离子通道活性对于理解许多细胞过程和筛选离子通道靶向候选药物至关重要。目前用于离子通道开放和关闭过程的电生理记录的金标准是过去几十年发展起来的膜片钳技术。尽管它已经引起了许多基本发现，但膜片钳方法使用紧紧压在细胞膜表面上的微量移液管并检测与离子通道活性相关的电流，这是难以操作的，低通量（一次一个膜片钳）并且通常是侵入性的（对细胞的损伤）。该项目将开发一种新的光学方法来测量由于膜中离子通道的打开和关闭而引起的细胞电导变化。该方法是基于电导信号转换成等离子体信号，可以光学成像，而不使用微量移液管。这种范式转换方法有望以毫秒级的时间和亚微米级的空间分辨率非侵入性地映射单细胞上的离子通道活性。该装置与传统的光学、荧光和表面等离子体共振成像技术完全兼容，从而允许将多种成像技术同时应用于同一细胞，并提供关于离子通道的全面和互补的信息。这种成像技术有望为药物-离子通道受体相互作用提供新的见解，并为高通量离子通道靶向药物发现提供新的工具。该项目的具体目标包括：1）开发用于绘制活细胞中离子通道活动的等离子体技术; 2）使用烟碱乙酰胆碱受体作为模型系统建立等离子体技术在电生理学研究中的价值; 3）展示多功能测量并使用膜片钳和荧光成像技术验证等离子体技术。 公共卫生相关性：膜片钳技术是研究细胞离子通道的有力工具，但操作困难、通量低且常为侵入性。本项目开发了一种测量电导的光学方法，使得能够以高空间和时间分辨率非侵入性地绘制离子通道开放和关闭活动。这种前所未有的能力，预计将提供新的见解离子通道活动和高通量筛选离子通道靶向药物的新工具。

DESCRIPTION (provided by applicant): Studying and monitoring ion channel activities of single cells are critical for understanding many cellular processes, and for screening ion-channel targeted drug candidates. The current gold standard for electrophysiological recording of ion channel opening and closing processes is the patch clamp technique developed over the past several decades. Although it has been responsible for many fundamental discoveries, the patch clamp method uses a micropipette pressed tightly onto a cell membrane surface and detects electrical current associated with the ion channel activities, which is difficult to operate, low throughput (one- patch at a time) and often invasive (damage to the cell). The proposed project will develop a novel optical method to measure cellular electrical conductance changes due to the opening and closing of ions channels in the membrane. The method is based on the conversion of an electrical conductance signal into a plasmonic signal that can be imaged optically without using the micropipette. This paradigm shift approach promises non- invasive mapping of ion channel activities on single cells with millisecond temporal and sub-micron spatial resolution. The setup is fully compatible with the conventional optical, fluorescence and surface plasmon resonance imaging techniques, thus allowing for simultaneous application of multiple imaging techniques to the same cell, and providing comprehensive and complementary information on ion channels. Such an imaging technique is expected to lead to new insights into drug-ion channel receptor interactions and a new tool for high throughput ion-channel targeted drug discovery. The specific aims of the project includes: 1) develop the plasmonic technique for mapping of ion channel activities in living cells; 2) establish the value of the plasmonic techniqu for electrophysiological studies using nicotinic acetylcholine receptors as a model system; 3) demonstrate multifunctional measurements and validate the plasmonic technique with the patch clamp and fluorescence imaging techniques. PUBLIC HEALTH RELEVANCE: Patch clamp technique is a powerful tool for studying ion channels of cells, but it is difficult to operate, low throughput and often invasive. The present project develops an optical method to measure electrical conductance, making it possible to map ion channel opening and closing activities noninvasively with high spatial and temporal resolution. This unprecedented capability is anticipated to provide new insights into ion channel activities and a new tool for high throughput screening of ion-channel targeted drugs.