Cell Endoscopy with Nanowire Probe

描述（由申请人提供）：在该R21计划中，我们建议开发一种用于单细胞内窥镜检查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集成的柔性纳米线的尖端上的近场扫描光学显微镜（NSOM）探针。该计划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基础上。我们广泛的能力和专业知识将使我们处于独特的地位，以实现潜在的突破，并在单细胞成像和探测方面开辟新的可能性。开发这种柔性纳米线探针将使我们能够监测单个活细胞内的体内生物过程，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，将纳米线直接纳米操纵和附着到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的这项研究。一种是传统的介电材料，如SnO 2，另一种是具有强非线性光学特性的材料，如KNbO 3。有几个关键特征与这些提出的细胞内窥镜探头：1。微创治疗。所使用的纳米线通常具有低于100 nm的直径和高纵横比。这种结构特征确保了所提出的平台的非侵入性。2.高灵活性。这些纳米线是高度柔性的，但机械坚固。这些纳米线中的扭曲和弯曲不会引起显著的光传播损耗，并且极大地简化了此类探针在单细胞成像中的应用。3.高折射率。因此，这些纳米线即使在高折射率生理液体和/或活细胞环境中也是有效的亚波长光波导。4.具有高度局域化激发和检测方案的倏逝波光学传感原理。由于这些纳米线的亚波长光波导性质，这些纳米线的探针体积可以被限制到纳米线的最尖端（即，低至皮科升和毫微微升）。5.非线性光学转换能力。将非线性光学纳米线应用到所提出的探针平台中将引入两个重要特征：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IR光束，并在另一端使用可见光或UV输出来进行细胞成像/探测。使用IR作为输入光束将再次极大地有益于真实生理环境中的整个成像过程。这种新的纳米线探针承诺细胞内成像与大大增强的三维空间分辨率以及时间分辨率。此外，这些纳米线探针还可以用于从单个活细胞中定位递送或提取化学品（蛋白质/DNA），与常规递送/提取方法相比具有大大改善的空间分辨率。

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.