Advances and perspectives in carbon dot-based fluorescent probes: Mechanism, and application

•The unique physical and chemical properties of CD-based fluorescent probes are discussed.•The six sensing mechanisms of CD-based fluorescent probes are introduced in detail.•The sensing application of CD-based fluorescent probes are elaborated.•The challenges of CD-based fluorescent probes and possible strategies to overcome them are also summarized. Due to the advantages of in situ, real-time, and non-destructive detection of target molecules, fluorescent probes have become an indispensable tool in the fields of disease diagnosis and environmental and food safety monitoring. However, with the development of modern science and technology, sensing techniques have new challenges and requirements, such as increased sensitivity, better selectivity, and high-throughput visual detection in complicated practical samples. Developing effective fluorescent probes is still ongoing research. Fluorescent carbon dots (CDs) are a novel carbon-based nanomaterial that have attracted tremendous attention because of their excellent biocompatibility, tunable fluorescence properties, good photostability, and easy synthesis and surface modification, and they have shown great potential in fluorescent sensing and imaging applications. In this review, we summarize the recent advances in CD-based fluorescent probes, including the design strategies, sensing mechanisms, and their applications in sensitive and selective detection of public safety substances, organic amines, phenols, bioactive molecules, biological enzymes, and inorganic salts. A future perspective is introduced to highlight the existing challenges and possible strategies to overcome the problems in practical application of currently developed CD-based fluorescent probes, which may be instructive to the design of effective fluorescent probes in the future.