Xu Yan, Yang Weitao, Zhang Bingbo
Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tongji University Cancer Center, Tongji University School of Medicine, Shanghai 200072, People's Republic of China.
Biomed Mater. 2021 Feb 3;16(2):022002. doi: 10.1088/1748-605X/abc745.
Optical imaging is a facile tool for visualizing biological processes and disease progression, but its image quality is largely limited by light-induced autofluorescence or background signals. To overcome this issue, low-background optical-imaging techniques including chemiluminescence imaging, afterglow imaging and photoacoustic imaging have been developed, based on their unique working mechanisms, which are: the detection of light emissions from chemical reactions, the cessation of light excitation before signal collection, and the detection of ultrasonic signals instead of light signals, respectively. Stimuli-responsive probes are highly desirable for improved imaging results since they can significantly reduce surrounding interference signals. Reactive oxygen species (ROS), which are closely implicated in a series of diseases such as cancer and inflammation, are frequently employed as initiators for responsive agents to selectively change the imaging signal. Thus, ROS-responsive agents incorporated into low-background imaging techniques can achieve a more promising imaging quality. In this review, recent advances in ROS-responsive probes for low-background optical-imaging techniques are summarized. Moreover, the approaches to improving the sensitivity of probes and tissue penetration depth are discussed in detail. In particular, we highlight the reaction mechanisms between the probes and ROS, revealing the potential for low-background optical imaging.
光学成像是一种用于可视化生物过程和疾病进展的便捷工具，但其图像质量在很大程度上受到光诱导自发荧光或背景信号的限制。为了克服这一问题，基于其独特的工作机制，已经开发了包括化学发光成像、余辉成像和光声成像在内的低背景光学成像技术，其工作机制分别为：检测化学反应产生的光发射、在信号采集前停止光激发以及检测超声信号而非光信号。由于刺激响应探针可以显著减少周围的干扰信号，因此对于改善成像结果非常理想。活性氧（ROS）与癌症和炎症等一系列疾病密切相关，经常被用作响应剂的引发剂，以选择性地改变成像信号。因此，将ROS响应剂纳入低背景成像技术可以实现更有前景的成像质量。在这篇综述中，总结了用于低背景光学成像技术的ROS响应探针的最新进展。此外，还详细讨论了提高探针灵敏度和组织穿透深度的方法。特别是，我们强调了探针与ROS之间的反应机制，揭示了低背景光学成像的潜力。
