Technology development for in vivo deep tissue imaging

描述（由申请人提供）：本研究计划的目标是探索新的激光技术、新的光谱窗口和用于深入散射组织成像的三光子荧光显微镜，然后展示体内生物成像的新方法。拟议的研究包括两个连续的推动力：第一个涉及开发一种新的高能激发源，用于探索1600和1800 nm之间的新光谱窗口（即，1700 nm光谱窗口），组织散射显著减少;第二个重点是展示基于三光子激发的体内深层组织成像的新方法，将信号与背景比提高几个数量级，并扩展多光子成像的深度穿透。该计划基于三大创新：（1）1700 nm光谱窗口，用于显著减少组织散射，（2）3 PE作为新的激发模态，用于同时改善SBR并扩展深层组织成像中荧光团的可及性，和（3）在1700-nm光谱窗口处，通过使用孤子自-在光子晶体棒中频移以产生从光纤激光器播种的能量、波长可调谐的孤子。我们的目标是展示新一代的多光子显微成像工具，它可以在完整的生物组织（如小鼠或大鼠大脑）内达到3 mm或更深的最终成像深度。该计划的成功完成将对各种生物和生物医学研究领域产生广泛的影响，这些领域需要在完整组织内进行高分辨率成像。

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.