Cell Endoscopy with Nanowire Probe

描述（由申请人提供）：在这个R21项目中，我们建议开发一个用于单细胞内窥镜的高度集成和高灵敏度的纳米线探针平台。在这个平台的中心是一个集成的柔性纳米线的尖端近场扫描光学显微镜（NSOM）探针。该项目将建立在我们在纳米结构合成/组装、系统集成和基于纳米线的光子学方面的广泛专业知识之上。我们广泛的能力和专业知识将使我们处于一个独特的位置，以实现潜在的突破，并开辟单细胞成像和探测的新可能性。这种柔性纳米线探针的开发将使我们能够监测单个活细胞内的生物过程，并将大大提高我们对细胞功能，细胞内生理过程，细胞信号通路的基本理解，从而彻底改变细胞生物学。我们将成功开发nsom -纳米线探针的原型，并展示其在细胞内成像和探测方面的原理验证应用。我们将开发和优化组装这些细胞内窥镜纳米线探针的策略，即直接纳米操作和将纳米线附着在NSOM探针上。我们将测试两种类型的纳米线作为亚波长光波导。一种是传统的介电材料，如SnO2，另一种是具有强非线性光学性质的材料，如KNbO3。这些提出的细胞内窥镜探针有几个关键特征：1。最小的侵袭性。所使用的纳米线直径一般在100纳米以下，具有高纵横比。这种结构特征确保了所提议平台的非侵入性。2. 高的灵活性。这些纳米线具有很高的柔韧性和机械强度。这些纳米线的扭曲和弯曲不会造成明显的光传播损失，极大地简化了这种探针在单细胞成像中的应用。3. 高折射率。因此，即使在高折射率生理液体和/或活细胞环境中，这些纳米线也是高效的亚波长光波导。4. 高局域激发的倏逝波光传感原理及检测方案。由于这些纳米线的亚波长光波导特性，这些纳米线的探针体积可以限制在纳米线的最尖端（即低至微升和飞升）。5. 非线性光转换能力。将非线性光学纳米线应用于所提出的探针平台将引入两个重要特性：亚波长波导和频率转换能力。我们将能够在纳米线的一端输入红外光束，并在另一端使用可见光或紫外线输出来进行细胞成像/探测。使用红外作为输入光束将再次大大有利于整个成像过程在现实的生理环境。这种新型纳米线探针有望大大提高三维空间分辨率和时间分辨率的细胞内成像。此外，这些纳米线探针还可用于从单个活细胞中定点递送或提取化学物质（蛋白质/ dna），与传统的递送/提取方法相比，其空间分辨率大大提高。

DESCRIPTION (provided by applicant): In this R21 program, we propose to develop a highly-integrated and highly-sensitive nanowire probe platform for single cell endoscopy. At the center of this platform lies the integrated flexible nanowire on the tip of a near- field scanning optical microscopy (NSOM) probe. This program will be built upon our extensive expertise in nanostructure synthesis/assembly, systems integration and nanowire based photonics. Our extensive capabilities and expertise will put us in a unique position to achieve potential breakthroughs and open up new possibilities in single cell imaging and probing. Developing of such flexible nanowire probes would enable us to monitor in-vivo biological processes within single living cells and will greatly improve our fundamental understanding of cell functions, intracellular physiological processes, cellular signal pathway, and thereby revolutionalizes cell biology. We will successfully develop a prototype for NSOM-nanowire probe and demonstrate its proof-of-principle applications for intracellular imaging and probing. We will develop and optimize strategies to assemble these cell endoscopy nanowire probes, i.e., direct nanomanipulation and attachment of nanowires onto NSOM probes. We will test two types of nanowires as sub-wavelength optical waveguides for this study. One is conventional dielectric materials such as SnO2, the other one being materials with strong non-linear optical properties, such as KNbO3. There are several key features associated with these proposed cell endoscopy probes: 1. Minimal invasiveness. The nanowires used will generally have diameters of sub-100 nm and with high aspect ratio. This structural feature ensures the non-invasiveness of the proposed platforms. 2. High flexibility. These nanowires are highly flexible and yet mechanically robust. The twisting and bending in these nanowires will not cause significant optical propagation loss, and greatly ease the application of such probes in single cell imaging. 3. High refractive index. As a result, these nanowires are efficient sub-wavelength optical waveguides even in high-index physiological liquids and/or living cell environments. 4. Evanescent wave optical sensing principle with highly localized excitation and detection scheme. Because of the subwavelength optical waveguiding nature of these nanowires, the probe volume of these nanowires can be limited to the very tip of the nanowires (i.e. down to pico- and femtoliter). 5. Nonlinear optical conversion capability. This application of the nonlinear optical nanowires into the proposed probe platforms will introduce two important features: subwavelength waveguiding and frequency conversion capability. We will be able to input IR beam at one end of the nanowires and use the visible or UV output on the other end to do the cell imaging/probing. The use of IR as input beam would again greatly benefit the entire imaging process in realistic physiological environments. Such novel nanowire probes promise intracellular imaging with greatly enhanced 3-dimensional spatial resolution as well as temporal resolution. In addition, these nanowire probes could also be used to spot- delivery or extraction of chemicals (proteins/DNAs) from single living cells with much improved spatial resolution as compared to conventional delivery/extraction methods.