Technology development for in vivo deep tissue imaging

项目描述（由申请人提供）：本项目旨在探索新的激光技术、新的光谱窗口和三光子荧光显微镜，用于深入散射组织的成像，并在体内生物成像中展示新的方法。提出的研究包括两个连续的重点：第一个涉及开发一种新的高能激发源，用于探索1600 - 1800 nm之间的新光谱窗口（即1700 nm光谱窗口），显著降低组织散射；第二个重点是展示基于三光子激发的体内深部组织成像的新方法，将信本比提高几个数量级，并扩展多光子成像的深度穿透。拟议的方案基于三个主要创新：(1) 1700-nm光谱窗口可显著降低组织散射；(2)3PE作为一种新的激发方式，可同时提高SBR并扩展荧光团在深部组织成像中的可及性；(3)在1700-nm光谱窗口为体内深部组织三光子荧光显微镜定制的激发源，利用光子晶体棒中的孤子自频移产生能量高、波长可调的光纤激光器种子孤子。我们的目标是展示新一代的多光子显微成像工具，该工具可以在完整的生物组织（如小鼠或大鼠大脑）内达到3毫米或以上的最终成像深度。该计划的成功完成将对需要在完整组织深处进行高分辨率成像的各种生物和生物医学研究领域产生广泛的影响。

DESCRIPTION (provided by applicant): The goal of this research program is to explore new laser technologies, new spectral windows, and three- photon fluorescence microscopy for imaging deep into scattering tissues, and then demonstrate the new methodologies in in vivo biological imaging. The proposed research consists of two sequential thrusts: the first involves the development of a novel energetic excitation source for the exploration of the new spectral window between 1600 and 1800 nm (i.e., the 1700-nm spectral window) with significantly reduced tissue scattering; the second thrust concentrates on demonstrating the new methodologies for in vivo deep tissue imaging based on three-photon excitation, improving the signal-to-background ratio by orders of magnitude and extending the depth penetration of multiphoton imaging. The proposed program is based on three major innovations: (1) 1700-nm spectral window for significantly reduced tissue scattering, (2) 3PE as a new excitation modality to simultaneously improve the SBR and extend the accessibility of fluorophores in deep tissue imaging, and (3) an excitation source tailored for in vivo deep tissue three-photon fluorescence microscopy at the 1700-nm spectral window by using soliton self-frequency shift in a photonic crystal rod to generate energetic, wavelength tunable solitons seeded from a fiber laser. We aim to demonstrate a new generation of multiphoton microscopic imaging tool that can reach an ultimate imaging depth of 3 mm or beyond within intact biological tissues such as the mouse or rat brain. The successful completion of this program will have a broad impact on a wide variety of biological and biomedical research fields where high-resolution imaging deep within intact tissue is required.