Molecular Probes for Autofluorescence-Free Optical Imaging

Abstract

Optical imaging is an indispensable tool in clinical diagnostics and fundamental biomedical research. Autofluorescence-free optical imaging, which eliminates real-time optical excitation to minimize background noise, enables clear visualization of biological architecture and physiopathological events deep within living subjects. Molecular probes especially developed for autofluorescence-free optical imaging have been proven to remarkably improve the imaging sensitivity, penetration depth, target specificity, and multiplexing capability. In this Review, we focus on the advancements of autofluorescence-free molecular probes through the lens of particular molecular or photophysical mechanisms that produce long-lasting luminescence after the cessation of light excitation. The versatile design strategies of these molecular probes are discussed along with a broad range of biological applications. Finally, challenges and perspectives are discussed to further advance the next-generation autofluorescence-free molecular probes for in vivo imaging and in vitro biosensors.

Chemiluminescent Probes Based on 1,2‐Dioxetane Structures For Bioimaging

“…The chemiluminescent probes for in vivo bioimaging in this minireview were summarized in Table 1 . The emission of some chemiluminescent probes has been extended to the NIR‐I region, which encourages us to explore in vivo imaging of deeper tissues [61] . Imaging at NIR‐II region overcomes the bottleneck of the penetration depth of the visible region, and it is currently a significant way to detect various biomarkers and report diseases efficiently [62] .…”

Persistent Luminescence‐Based Theranostics for Real‐Time Monitoring and Simultaneously Launching Photodynamic Therapy of Bacterial Infections

“…PL NPs afford long-lasting luminescence for minutes, hours, or even days after activation because they can store the excitation energy like optical batteries. [21] The unique self-illumination property could eliminate the autofluorescence interferences from tissues, and the near-infrared (NIR) afterglow offers better tissue penetration for imaging bacterial infection in deep tissues. [22] PL NPs also provide a self-luminous source in tissues to initiate PDT and persistently produce ROS without external light irradiation.…”

Dissecting extracellular and intracellular distribution of nanoparticles and their contribution to therapeutic response by monochromatic ratiometric imaging

“…Normally, the pharmacokinetics and biodistribution analyses are performed to establish the correlation between the delivery efficiency and therapeutic efficacy of nanomedicines. However, the routine quantitative and imaging methods can only provide their macroscopic distribution in tumor tissues, but fail to provide the detail information on intracellular and extracellular distributions of nanoparticles 17 – 19 .…”