CAREER: Tomographic microendoscopy for characterization of epithelial tissue structure and function

结肠内的早期癌症通常发生在组织的外层。随着癌症进展并侵入下方的肠壁，细胞之间的信号触发新的异常血管的形成。这些血管是扭曲的，其结构和成分各不相同。 与正常血管和毛细血管相比，也有显着差异。由于技术限制，直接研究活体中结肠组织的结构和功能的现有技术受到限制。该项目将开发一种可用于内窥镜的探头，内窥镜是一种标准的手术设备，可以对组织进行成像并重建组织特性的三维表示。 这项技术将适用于许多类型和尺寸的解剖学“管道”-包括消化道，胰管和其他结构。这种新型装置将用于检验结肠组织表面下血管的异常结构和组织与结直肠肿瘤生长和发展有关的假设。 同样，预期结直肠肿瘤的有效治疗将伴随着正常血管结构和组织的恢复。 在这个项目中，研究和教育部分通过本科生和研究生的指导和培训活动，课程开发和生物光子学特定的夏令营进行整合。 在夏令营中，学生将学习光的基本原理，以及如何利用光来回答生命科学中的研究问题。该项目的重点是开发一种新型的断层成像显微内窥镜（TIME）平台，能够对组织结构和灌注进行多模态表征。 该研究计划建立在PI先前开发的基于光纤束图像引导的显微内窥镜平台上，能够以亚细胞（3.5微米）分辨率对浅表组织进行成像。 所提出的平台将能够通过内窥镜（用于胃肠应用）或导管（用于血管内应用）展开，并能够对微血管系统进行多模式实时体内断层成像、组织灌注（血红蛋白含量和氧饱和度）的光谱定量以及浅表组织微结构的高分辨率成像。具体设计目标包括：1）外径为1 mm; 2）没有复杂的电流计或共振扫描系统; 3）具有成本效益的硬件（20，000美元），便于转化为临床应用; 4）断层扫描分辨率能够对直径约为20微米的皮下血管进行三维映射，深度可达500微米。研究计划围绕三个目标组织：1）使用纤维束图像引导显微内窥镜的断层图像重建-需要开发原型显微内窥镜设备和图像重建方法并在PDMS体模中进行验证; 2）用于血管造影应用的基于层析成像的断层显微内窥镜（F-TIME）-需要开发图像重建方法并在光学体模中进行验证，以及3）TIME在结肠直肠癌原位小鼠模型中肿瘤血管和灌注特征的应用--该奖项反映了NSF的法定使命，并通过利用基金会的知识价值和更广泛的影响进行评估，被认为值得支持审查标准。

Early cancer within the colon typically arises in the outer layers of the tissue. As cancer progresses and invades into the bowel wall beneath, a signals between cells trigger the formation of new, abnormal blood vessels. These vessels are twisted and have variations in their structure and components. There are also significant differences when compared to normal blood vessels and capillaries. Existing techniques to directly investigate the colon tissue's structure and function in a living subject are limited due to technological constraints. This project will develop a probe that can be used on an endoscope, a standard piece of surgical equipment, that can image the tissue and reconstruct a three-dimensional representation of the tissue properties. This technology will be useful for anatomical "tubes" of many types and sizes - including the digestive tract, pancreatic duct, and other structures. This novel device will be used to test the hypothesis that an abnormal structure and organization of blood vessels beneath the surface of the colon tissue is related to colorectal tumor growth and development. Similarly, it is expected that effective treatment of colorectal tumors will be accompanied by a return of normal blood vessel structure and organization. Within this project, research and educational components are integrated through undergraduate and graduate student mentoring and training activities, course development, and a Biophotonics-specific summer camp. In the summer camp, students will learn the fundamentals of light and how light can be used to answer research questions in the life sciences.The project focuses on developing a novel Tomographic Imaging MicroEndoscopy (TIME) platform, capable of multimodal characterization of tissue structure and perfusion. The Research Plan builds on an optical fiber bundle image guide-based microendoscopy platform, previously developed by the PI, capable of imaging superficial tissues at subcellular (3.5 micron) resolution. The proposed platform will be capable of deployment via endoscope (for gastrointestinal applications) or catheter (for intravascular applications) and be capable of multimodal real-time in vivo tomographic imaging of microvasculature, spectroscopic quantification of tissue perfusion (hemoglobin content and oxygen saturation) and high-resolution imaging of superficial tissue microarchitecture. Specific design goals include: 1) Outer diameter of 1mm; 2) No complex galvanometric or resonant scanning systems; 3) Cost-effective hardware ($20,000 USD) to facilitate translation to clinical applications and 4)Tomographic resolution capable of three dimensional mapping of subsurface vessels of ~20 micron diameter, down to 500 micron depth. The Research Plan is organized around three objectives: 1) Tomographic-image reconstruction using a fiber bundle image guide microendoscope--requiring development of the prototype microendoscopy device and image reconstruction methods and validation in PDMS phantoms; 2) Fluorescence-based tomographic microendoscopy (F-TIME) for angiographic applications--requiring development of image reconstruction methods and validation in optical phantoms and 3) Application of TIME for characterization of tumor vasculature and perfusion in an orthotopic mouse model of colorectal cancer--requiring mapping the in vivo microenvironment during tumor development and characterizing the tumor vasculature in response to a therapeutic intervention.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.