Revealing the Adverse Effects of Trace Amount Broad‐Spectrum Antimicrobial: a Direct and Sensitive Visualization Method Based on Carbon Nanoprobe

Abstract The widespread use of broad‐spectrum antimicrobials has accelerated their entry into aquatic environment, which in turn can adversely affect aquatic organisms and humans, especially in the COVID‐19 outbreak and the post‐pandemic era. For early detection and intervention of adverse effects, this study develops a new carbon nanoprobe (CNP) that can reveal the adverse effects of trace amount triclosan (TCS), a commonly used broad‐spectrum antimicrobial (BSA), through a direct visualization method. CNP has excellent fluorescent properties and strong positive charges, which can be applied as fluorescent indicator and trapped in mitochondria by electrostatic attraction. The highly sensitive responsiveness of CNP to mitochondrial membrane potential ensures the visualization method can be used for monitoring the adverse effects of TCS. The trace amount TCS monitoring is achieved according to the decrease of fluorescence signal in mitochondria and the change of mitochondrial morphological structure from lines to dots. Moreover, monitoring TCS level in aquatic organisms of zebrafish is further realized. Compared with the morphological toxicity test, this visualizing strategy reveals the adverse effects in organisms under low‐dose TCS exposure more sensitively. This developed highly sensitive nanoprobe is cruical for direct BSA monitoring and thus prevents the harm of BSA to aquatic organisms and humans.