Aggregation‐Induced Nonlinear Optical Effects of AIEgen Nanocrystals for Ultradeep In Vivo Bioimaging
Aggregation‐Induced Nonlinear Optical Effects of AIEgen Nanocrystals for Ultradeep In Vivo Bioimaging
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DOI：
10.1002/adma.201904799
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发表时间：
2019-07
影响因子：
29.4
通讯作者：
Zheng Zheng-Zheng;Dongyu Li;Zhiyang Liu;Hui-Qing Peng;H. Sung;R. K. Kwok;Ian D. Williams;J. Lam;J. Qian;B. Tang
中科院分区：
文献类型：
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作者：
Zheng Zheng-Zheng;Dongyu Li;Zhiyang Liu;Hui-Qing Peng;H. Sung;R. K. Kwok;Ian D. Williams;J. Lam;J. Qian;B. Tang
非线性光学显微镜因其独特的深度光学切片、高空间分辨率成像和生物样本 3D 重建功能而成为生物成像研究的强大工具。开发具有强非线性光学效应，特别是三次谐波产生（THG）的有机荧光探针，有望将非线性显微成像应用于生物医学应用。在此，成功演示了一种基于具有明亮近红外发射的聚集诱导发射（AIE）发光体（DCCN）制备有机纳米晶体的简单方法。在纳米颗粒中观察到聚集引起的非线性光学效应，包括 DCCN 的双光子荧光 (2PF)、三光子荧光 (3PF) 和 THG，特别是晶体纳米颗粒。 DCCN 纳米晶体分别成功应用于 1040 nm NIR-II 激发下的 2PF 显微镜和 1560 nm NIR-II 激发下的 THG 显微镜，以重建小鼠脑血管系统的 3D 血管系统。令人印象深刻的是，THG 显微镜提供了比 2PF 显微镜更高的空间分辨率和亮度，并且可以可视化小鼠大脑中最深 800 µm 处直径约为 2.7 µm 的小血管。因此，这有望激发对用于多模态非线性光学显微镜的具有多重非线性的先进 AIE 材料（特别是 THG）的开发的新见解。
Nonlinear optical microscopy has become a powerful tool in bioimaging research due to its unique capabilities of deep optical sectioning, high‐spatial‐resolution imaging, and 3D reconstruction of biological specimens. Developing organic fluorescent probes with strong nonlinear optical effects, in particular third‐harmonic generation (THG), is promising for exploiting nonlinear microscopic imaging for biomedical applications. Herein, a simple method for preparing organic nanocrystals based on an aggregation‐induced emission (AIE) luminogen (DCCN) with bright near‐infrared emission is successfully demonstrated. Aggregation‐induced nonlinear optical effects, including two‐photon fluorescence (2PF), three‐photon fluorescence (3PF), and THG, of DCCN are observed in nanoparticles, especially for crystalline nanoparticles. The nanocrystals of DCCN are successfully applied for 2PF microscopy at 1040 nm NIR‐II excitation and THG microscopy at 1560 nm NIR‐II excitation, respectively, to reconstruct the 3D vasculature of the mouse cerebral vasculature. Impressively, the THG microscopy provides much higher spatial resolution and brightness than the 2PF microscopy and can visualize small vessels with diameters of ≈2.7 µm at the deepest depth of 800 µm in a mouse brain. Thus, this is expected to inspire new insights into the development of advanced AIE materials with multiple nonlinearity, in particular THG, for multimodal nonlinear optical microscopy.