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

简介：S.Scott Saavedra研究所：亚利桑那大学建议编号：0428885智能优点：该项目专注于开发新的光学/电化学、基于通道波导的传感平台，该平台可响应与化学门控离子通道受体(本研究第一阶段中的KATP通道)重组为平面支撑(聚)脂双层(PSLB)的分析物。蛋白质-脂膜换能器将连接到自组装的导电聚合物(SA-CP)膜上，SA-CP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的结合转换为电化学(电位/阻抗)和光学(吸光度/荧光)响应，以提供对传感器响应的机械理解，并允许优化传感器层。背向耦合(近场)波导检测荧光响应是该传感器的独特功能之一，它的发展将使一种重要的新的芯片式传感器技术成为可能，集平面内激励和检测于一体。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，该几何结构既为离子敏感生色团的激发提供强大的瞬逝场，又提供增强其发光响应的波导背向耦合的模式结构。这将导致传感器的光学组件与仿生传感材料无缝集成，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，这是我们机制研究的一个基本特征，其中吸光度和发光响应与电位/阻抗响应同时跟踪。EA-CH-IOW的创建需要优化沉积技术，并解决材料兼容性问题，将其与“软”换能器层集成在一起。c)由功能化(聚)噻吩层和(聚)反离子组成的超薄亲水性CP膜将在波导表面自组装。SA-CP层将作为具有嵌入离子通道的PSLB的水膨胀的“缓冲”，为跨膜离子通量的变化创造适当的电化学转导环境。通过将(聚)噻吩层与冠醚修饰的染料共聚，可以实现超灵敏的光谱检测，这些染料在与金属离子结合时，其发光性能会发生显著变化。自组装将用于将这些染料限制在波导/CP界面附近，这对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可产生稳定的共形脂质双层，将用于重建跨膜K+通道(更复杂配体门控通道的原型)，从而创建生物活性转换器层，将交联聚合物的稳定性与脂膜的生物相容性结合在一起。通过ITO/CP支持的PSLB进行配体门控、离子传输的演示将为基于仿生聚(脂)膜化学的传感器的广泛应用开辟道路。广泛的影响：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，还为这一努力设想了几项教育和推广活动，包括：i)与亚利桑那州普雷斯科特的亚瓦派学院发展新的互动，除了为亚利桑那州的本科生提供研究机会外，还为他们的一些二年级学生提供研究机会；二)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--信息技术材料和器件的EHRDO活动(华盛顿大学，牵头机构)。

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).