近红外二区（900~1 880 nm，the Second Near-Infrared Region，NIR-II）荧光宽场显微成像技术是当前大深度活体成像的一大研究热点，在基础研究和临床应用方面都拥有巨大的潜力。对比可见光（360~760 nm）和近红外一区（760~900 nm，the First Near-Infrared Region，NIR-I）的成像，NIR-II荧光宽场显微成像技术在活体层面具有更高的清晰度和更深的组织穿透。在NIR-II宏观成像基础上，对组织微结构清晰成像的需求迫使成像试剂持续发展，成像系统不断精进。目前，NIR-II荧光宽场显微成像技术在脉管显微造影、肿瘤精确分析、炎症准确追踪等生物应用上都获得一系列突破，相关研究对象包含啮齿类动物（如小鼠，大鼠）及灵长类动物（如狨猴，猕猴）等。将来随着仪器商业化和国产化突破，成像试剂安全性逐步提高，NIR-II荧光宽场显微成像应用价值将不断攀升。本文从NIR-II荧光成像的机制及优势展开讨论，综述NIR-II荧光宽场显微成像的系统特点和演进历史，以及其在不同生物模型上活体成像方面的最新探索和前景展望，以期推动NIR-II荧光宽场显微成像技术进一步普及。

Exosomes are lipid bilayer vesicles released by cells and serve as natural carriers for cell–cell communication. Exosomes provide a promising approach to the diagnosis and treatment of diseases and are considered as an alternative to cell therapy. However, one main restriction in their clinical application is that the current understanding of these vesicles, especially their in vivo behaviors and distributions, remains inadequate. Here, we reviewed the current and emerging methods for in vivo imaging and tracking of exosomes, including fluorescence imaging, bioluminescence imaging, nuclear imaging, X-ray imaging, magnetic resonance imaging, photoacoustic imaging, and multimodal imaging. In vivo imaging and tracking of exosomes by these methods can help researchers further understand their uptake mechanism, biodistribution, migration, function, and therapeutic performance. The pioneering studies in this field can elucidate many unknown exosomal behaviors at different levels. We discussed the advantages and limitations of each labeling and imaging strategy. The advances in labeling and in vivo imaging will expand our understanding of exosomes and promote their clinical application. We finally provide a perspective and discuss several important issues that need to be explored in future research. This review highlights the values of efficient, sensitive, and biocompatible exosome labeling and imaging techniques in disease theranostics.

Functionalized black phosphorus (BP) nanosheets have been considered as promising nanoagents in cancer therapy due to their excellent photothermal conversion efficiency. However, it is still difficult to visually monitor the dynamic localization of BP nanoagents in cancer cells. In this paper, we systematically studied the second-harmonic generation (SHG) signals originating from exfoliated BP nanosheets. Interestingly, under the excitation of a high frequency pulsed laser at 950 nm, the SHG signals of BP nanosheets in vitro are almost undetectable because of their poor stability. However, the intracellular SHG signals from BP nanosheets could be measured by in vivo optical imaging due to the efficient enrichment of living HeLa cells. Moreover, the SHG signal intensity from BP nanosheets increases with the prolonged incubation time. It can be expected that the BP nanosheets could be a promising intracellular SHG nanoprobe employed for visually in vivo biomedical imaging in practical cancer photothermal therapy (PIT).

拟设计在体内低毒、 靶向肿瘤细胞的抗癌多肽（记: GPG）, 克服在抗癌治疗中使用化学类药物存在的缺点, 探讨用荧光光谱评价靶向肽对肿瘤肿块包覆状况的方法; 进行仅用一组基于双报告基团的小鼠模型（用EGFP转染的鼠肝肿瘤细胞H22, 记: H22-EGFP与荧光染料Cy7标记的GPG, 记: Cy7-GPG, 作报告基团）, 就能完成抗癌肽体内主要性能监测的研究。 用H22-EGFP构建小鼠移植瘤模型, 尾静脉注射Cy7-GPG后, 用成像仪（Ex=750 nm）观察到肿瘤的荧光光子数不断增大, 从第4 h的(3.90±0.260)×106 photons·(s·cm2)-1(单位下同)升至第24 h的(1.28±0.330)×108, 橙色荧光全部聚集到肿瘤上, 而对照组中Cy7的荧光没有聚集在肿瘤上, 且肿瘤上光子数也无明显变化; 此时, 用成像仪在实验组同一只鼠上, 分别用750和488 nm激发波长录得包覆状物和实际肿瘤肿块的图片, 表明它们的大小和形状一致; 以上两项测定后, 再每2 d一次往上述实验组鼠体内注射GPG, 在成像仪上(Ex=488 nm)监测到它们的肿瘤变小, 荧光光子数逐渐降低, 从第2 d的(4.15±0.291)×106降至第56 d的(4.75±0.283)×104, 空白对照组正相反。 GPG与化学药物环磷酰胺抗癌活性相当, 但后者对小鼠毒副作用严重; 最后, 往上述GPG药效实验组鼠体内注射Cy7-GPG, 48 h后处死小鼠, 取出内脏器官及肿瘤肿块, 在成像仪上（Ex=750 nm）录得它们的荧光光子数。 实验表明GPG靶向性强、 对肿瘤肿块包覆程度高、 药效强, 对其他主要脏器无毒副作用。 本文构建的基于双报告基团荧光成像模型, 可监测靶标被包覆状况, 克服了传统只能对靶向肽靶向功能进行评价的弊端, 增进对药物作用机理的认识; 本文仅消耗一组实验鼠模型, 节约实验成本、 简捷地监测了靶向肽主要性能, 表明GPG在体内性能较好, 具有应用价值。

Despite the unique advantages of optical microscopy for molecular specific high resolution imaging of living structure in both space and time, current applications are mostly limited to research settings. This is due to the aberrations and multiple scattering that is induced by the inhomogeneous refractive boundaries that are inherent to biological systems. However, recent developments in adaptive optics and wavefront shaping have shown that high resolution optical imaging is not fundamentally limited only to the observation of single cells, but can be signifi- cantly enhanced to realize deep tissue imaging. To provide insight into how these two closely related fields can expand the limits of bio imaging, we review the recent progresses in their performance and applicable range of studies as well as potential future research directions to push the limits of deep tissue imaging.

线扫描共聚焦成像技术基于共聚焦成像原理,使用线光束一维扫描照明样品以提高成像速率;通过共焦狭缝滤除样品成像光束中的非聚焦层面杂散光,提高成像分辨率和对比度;近年来,该技术因分辨率高、成像快、成像视场大、系统结构简单等优点而在生物医学成像中的应用越来越广泛。介绍了线扫描共聚焦成像技术的基本原理,列举了成像系统的主要参数及其影响因素,并举例说明了其在生物医学成像,尤其是眼底成像和生物组织细胞观察等方面的应用,最后总结了该技术的优缺点及其应用前景。

为实现高信噪比(SNR)的深层生物组织成像，结合了激光扫描共聚焦成像技术和近红外(NIR)荧光成像技术，根据近红外荧光成像要求设计了一套激光扫描共聚焦近红外荧光成像实验系统，对注入近红外荧光染料LDS925 小鼠的尾部成像后获得了小鼠尾部近红外荧光图像和近红外共聚焦荧光图像。实验结果表明小鼠尾部近红外共聚焦荧光图像信噪比显著优于小鼠尾部近红外荧光图像，采用均方差和峰谷(PV)值进行评估时，近红外荧光成像荧光信号强度分布的均方差值和PV 值分别为864 和102；共聚焦荧光成像的荧光信号强度分布的均方差值和PV 值分别为1459 和255；进一步表明激光扫描共聚焦成像技术在近红外荧光成像中应用是可行的，可以实现深层组织的高信噪比共聚焦成像。