SST: Ligand-Gated, Ion Channel Sensing Membranes Coupled to Novel, Fluorescence-Based Waveguide Platforms Through Conducting Polymer Supports

摘要：S. Scott Saavedra机构：ArizonaProposal Number：0428885智力优点：该项目的重点是开发新的光学/电化学，基于通道波导的传感平台，该平台对与化学门控离子通道受体（本研究第一阶段中的KATP通道）相互作用的分析物做出响应，该分析物重组成平面支持的（聚）脂质双层（PSLB）。 蛋白-脂质膜换能器将被拴系到自组装的导电聚合物（SA-CP）膜上，该膜与低浓度的离子敏感荧光染料共聚，支撑在电活性通道集成光波导（EA-CH-IOW）上。 传感器平台将分析物结合到电化学（电位/阻抗）和光学（吸光度/荧光）响应中，以提供对传感器响应的机械理解，并允许优化换能器层。荧光响应的后耦合（近场）波导检测是所提出的传感器的独特功能之一，其发展将使一个重要的新的芯片式传感器技术，集成，面内激发和检测。 具体的挑战和里程碑包括：a）必须开发具有双重光学限制几何结构的多层通道波导，其提供用于激发离子敏感发色团的强倏逝场和增强其发光响应的波导反向耦合的模式结构。 这将导致具有与仿生传感材料无缝集成的光学元件的传感器，其易于制造、部署和集成到光通信系统中。B）波导的上层将是电活性的，这是我们的机理研究的基本特征，其中吸收和发光响应与电位/阻抗响应同时跟踪。 EA-CH-IOW的产生需要优化沉积技术，并解决材料相容性问题以将它们与“软”换能器层集成。c）由官能化（聚）噻吩和（聚）抗衡离子组成的亲水性CP膜将自组装在波导表面上。 SA-CP层将用作具有嵌入离子通道的PSLB的水溶胀“垫”，以产生用于跨膜离子通量变化的电化学转导的适当环境。 超灵敏的光谱检测方式将促进（聚）噻吩层与冠醚改性的染料，表现出显着的变化，在其发光特性后，金属离子结合的共聚。 自组装将用于将这些染料限制在波导/CP界面附近，这对于实现反向耦合荧光检测模式至关重要。d）新的可聚合脂质技术，其产生稳定的共形脂质双层，将用于重建跨膜K+通道（更复杂的配体门控通道的原型），产生结合了交联聚合物的稳定性与脂质膜的生物相容性的联合收割机的生物活性换能器层。通过ITO/CP支持的PSLB证明配体门控离子传输将为基于仿生聚（脂质）膜化学的传感器的广泛应用开辟道路。除了为亚利桑那大学的研究生、本科生和博士后研究员提供跨学科培训外，他们中的许多人都是科学领域代表性不足的群体的成员，为此，设想开展几项教育和外联活动，包括：i）与Yavapai学院开展新的互动（普雷斯科特，亚利桑那州），提供研究机会，为他们的一些二年级学生，除了研究机会，为本科生在亚利桑那州; ㈡开发一个关于ATR波导技术的新的网络课程模块，纳入我们的NSF科学和技术中心-信息技术材料和设备（华盛顿大学，牵头机构）的EHRDO活动。

ABSTRACTPI: S. Scott Saavedra Institution: University of ArizonaProposal Number: 0428885Intellectual Merit: This project focuses on the development of new optical/electrochemical, channel waveguide-based sensing platforms which respond to analytes that interact with chemically-gated ion channel receptors (KATP channels in the first phases of this research) reconstituted into a planar supported (poly)lipid bilayer (PSLB). The proteo-lipid membrane transducer will be tethered to a self-assembled, conducting polymer (SA-CP) film, co-polymerized with low concentrations of ion-sensitive fluorescent dyes, supported on a electroactive channel integrated optical waveguide (EA-CH-IOW). The sensor platform will transduce the binding of analytes into both electrochemical (potentiometric/impedance) and optical (absorbance/fluorescence) responses to provide a mechanistic understanding of sensor responses and allow optimization of the transducer layers. Backcoupled (near-field) waveguide detection of the fluorescence response is one of the unique features of this proposed sensor, and its development will enable a significant new chip-like sensor technology, with integrated, in-plane excitation and detection. Specific challenges and milestones for include:a) Multilayer channel waveguides must be developed with dual optical confinement geometries that provide both strong evanescent fields for excitation of ion-sensitive chromophores and a mode structure that enhances waveguide back-coupling of their luminescence response. This should lead to sensors with optical components seamlessly integrated with biomimetic sensing materials, which are easy to make, deploy, and integrate into optical communications systems.b) The upper layer of the waveguide will be electroactive, an essential feature of our mechanistic studies, where absorbance and luminescence responses are tracked simultaneously with potentiometric/impedance responses. The creation of the EA-CH-IOW requires optimizing deposition technologies, and solving material compatibility issues to integrate them with "soft" transducer layers.c) An ultrathin, hydrophilic CP film, composed of a functionalized (poly)thiophene and a (poly)counter-ion, will be self-assembled on the waveguide surface. The SA-CP layer will function as a water-swollen "cushion" for the PSLB with embedded ion channels, to create the proper environment for electrochemical transduction of changes in transmembrane ion flux. Ultra-sensitive spectral detection modalities will be facilitated by co-polymerization of the (poly)thiophene layer with crown-ether-modified dyes that exhibit significant changes in their luminescence properties upon metal ion binding. Self-assembly will be used to confine these dyes near the waveguide/CP interface, which is critical to the realization of back-coupled fluorescence detection modalities.d) New polymerizable lipid technologies, which produce stable, conformal lipid bilayers, will be used to reconstitute transmembrane K+-channels (prototypes for more complex ligand-gated channels), creating bioactive transducer layers that combine the stability of a cross-linked polymer with the biocompatibility of a lipid membrane. Demonstration of ligand-gated, ion transport through ITO/CP-supported PSLBs will open the way for broad implementation of sensors based on biomimetic poly(lipid) membrane chemistries.Broader Impact: In addition to the cross-disciplinary training provided for graduate and undergraduate students and postdoctoral fellows at the University of Arizona, many of whom are members of groups under-represented in science, several Education and Outreach activities are envisioned for this effort, including: i) Development of a new interaction with Yavapai College (Prescott, Arizona), providing research opportunities for some of their second year students, in addition to research opportunities for undergraduate students at Arizona; ii) Development of a new web-based curricular module on ATR waveguide technologies, integrated into the EHRDO activities of our NSF Science and Technology Center - Materials and Devices for Information Technology (University of Washington, lead institution).