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Concern about food safety triggers demand on rapid, accurate and on-site detection of foodborne pathogens. Among various fluorescent probes for detection, carbon dots (CDs) prepared by carbonization of carbon-rich raw materials show extraordinary performance for their excellent and tailorable photoluminescence property, as well as their facilely gained specificity by surface customization and modification. CDs-based fluorescent probes play a crucial role in many pathogenic bacteria sensing systems. In addition, microfluidic technology with characteristics of portability and functional integration is expected to combine with CDs-based fluorescent probes for point-of-care testing (POCT), which can further enhance the detection property of CDs-based fluorescent probes. Here, this paper reviews CDs-based bacterial detection methods and systems, including the structural modulation of fluorescent probes and pathogenic bacteria detection mechanisms, and describes the potential of combining CDs with microfluidic technology, providing reference for the development of novel rapid detection technology for pathogenic bacteria in food., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

N 2 H 4 is a common raw material used in the production of pesticides and has good water solubility, so it may contaminate water sources and eventually enter living organisms, causing serious health problems. Viscosity is an important indicator of the cellular microenvironment and an early warning signal for many diseases. The high reactivity of hydrazine depletes glutathione (GSH) in hepatocytes, causing oxidative stress ultimately leading to significant changes in intracellular viscosity and even death. Therefore, it is particularly important to develop an effective method to detect N 2 H 4 and viscosity in environmental and biological systems. On this basis, we developed two fluorescent probes, BDD and BHD, based on xanthene and 2-benzothiazole acetonitrile. The experimental results show that BHD and BDD have good imaging capabilities for N 2 H 4 in cells, zebrafish and Arabidopsis. BHD and BDD also showed sensitive detection and fluorescence enhancement in the near-infrared region when the intracellular viscosity was changed. Notably, the probe BDD has also successfully imaged N 2 H 4 in a variety of real water samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen peroxide (H 2 O 2 ) is a reactive oxygen species (ROS) that can be used as a marker for the occurrence of oxidative stress in the organism. Lysosomes serve as intracellular digestive sites, and when the concentration of H 2 O 2 in them is abnormal, lysosomal function is often impaired, leading to the development of diseases. Hydrogen sulfide (H 2 S) acts as a gaseous signaling molecule that scavenges H 2 O 2 from cells and tissues, thereby maintaining the redox environment of the body. However, most of the reported hydrogen peroxide fluorescent probes so far can only detect H 2 O 2 , but cannot maintain the intracellular redox environment. In this paper, an H 2 O 2 fluorescent probe LN-HOD with lysosomal targeting properties was designed and synthesized by combining the H 2 O 2 recognition site with a naphthylamine fluorophore via a thiocarbamate moiety. The probe has the advantages of large Stokes shift (110 nm), high sensitivity and good H 2 S release capability. The probe LN-HOD can be used to detect H 2 O 2 in cells, zebrafish and plant roots. In addition, LN-HOD detects changes in the concentration of H 2 O 2 in plant roots when Arabidopsis is stressed by cadmium ion (Cd 2+ ). And through its ability to release H 2 S, it can help to remove excess H 2 O 2 and maintain the redox environment in cells, zebrafish and plant roots. The present work provides new ideas for the detection and assisted removal of H 2 O 2 , which contributes to the in-depth study of the cellular microenvironment in organisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)