Monoamine oxidases (MAOs) are a class of flavin enzymes that are mainly present in the outer membrane of mitochondria and play a crucial role in maintaining the homeostasis of monoamine neurotransmitters in the central nervous system. Furthermore, expression of MAOs is associated with the functions of peripheral organs. Dysfunction of MAOs is relevant in a variety of diseases such as neurodegenerative diseases, heart failure, metabolic disorders, and cancers. Monoamine oxidases have two isoenzymes, namely, monoamine oxidase A (MAO‐A) and monoamine oxidase B (MAO‐B). Therefore, the development of reliable and specific methods to detect these two isoenzymes is of great significance for the in‐depth understanding of their functions in biological systems, and for further promoting the clinical diagnosis and treatment of MAO‐related diseases. This review mainly focuses on the advances in small molecular probes for the specific imaging of MAO‐A and MAO‐B, including radiolabeled probes, fluorescent probes, and a ¹⁹F magnetic resonance imaging probe. In addition, applications of these probes for detecting MAO expression levels in cells, tissues, animal models, and patients are described. Finally, the challenges and perspectives of developing novel MAO imaging probes are also highlighted.

In the realm of pharmaceutical advancement, the transformative prowess of nanotechnology shines through its precision-targeted drug delivery and amplified therapeutic effects. This paper ventures into the realm of radiolabeling techniques for unraveling the intricate choreography of drug kinetics within the bloodstream which encompass the delicate stages of absorption, distribution, metabolism, and excretion. Through the magical lens of the radiolabel, a real-time spectacle unfolds, providing invaluable insights into the safety and efficacy of nanomedicine interventions. Amid the labyrinthine complexities of drug-organism interactions and the lack of universal protocols for nanomedicine preparation, radiolabeling technology has emerged as a guiding constellation. The paper systematically assesses the methods commonly employed for pharmacokinetic studies, delves into the manifold advantages and techniques of radiolabel methods within the nanomedicine landscape, closely examines their application across a spectrum of pharmacokinetic studies and thoughtfully addresses the challenges they may pose. Embark on this illuminating odyssey—a journey that peers into the microcosm of nanomedicine, deciphering its dynamic interplay within the bloodstream through the luminary insights of radiolabeled tracing techniques.

The capping agents for liquid metal (LM) nanodroplets in aqueous solutions are restricted to thiol-containing and positively-charged molecules or macromolecules. However, both thiolate-metal complex and electrostatic interaction are liable to detachment upon strong mechanical forces such as sonication, leading to limited stability and applications. To address this, we utilized ultrasmall water soluble melanin nanoparticles (MNPs) as the capping agent, which exhibited strong metal binding capability with the oxide layer of gallium based LMs and resulted in enhanced stability. Interestingly, shape-controlled synthesis of LM nanodroplets can be achieved by the incorporation of MNPs. Various EGaIn nanostructures including nanorice, nanosphere and nanorod were obtained by simply tuning the feed ratio, sonication time, and suspension temperature. Among these shapes, EGaIn nanorice has the best photothermal conversion efficiency, which could be leveraged for photothermal therapy.