Plasmonic mapping of ion channel activities in single cells

描述（由申请人提供）：研究和监测单个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。目前离子通道打开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。尽管膜片钳方法已经对许多基础发现负责，但它使用一个微移液管紧紧压在细胞膜表面，检测与离子通道活动相关的电流，这种方法操作困难，通量低（一次一个膜片），并且经常具有侵入性（对细胞造成损害）。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。该方法基于将电导信号转换为等离子体信号，无需使用微移液管即可进行光学成像。这种范式转换方法有望以毫秒时间和亚微米空间分辨率对单个细胞上的离子通道活动进行非侵入性测绘。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，从而允许对同一细胞同时应用多种成像技术，并提供离子通道的全面和互补信息。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，并成为高通量离子通道靶向药物发现的新工具。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)以烟碱乙酰胆碱受体为模型系统，确立等离子体技术在电生理研究中的价值；3)演示多功能测量，并利用膜片钳和荧光成像技术验证等离子体技术。

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.