Hypochlorite-Activated Fluorescence Emission and Antibacterial Activities of Imidazole Derivatives for Biological Applications.

The ability to detect hypochlorite (HOCl/ClO ^- ) in vivo is of great importance to identify and visualize infection. Here, we report the use of imidazoline-2-thione ( R ₁ SR ₂ ) probes, which act to both sense ClO ^- and kill bacteria. The N ₂ C=S moieties can recognize ClO ^- among various typical reactive oxygen species (ROS) and turn into imidazolium moieties ( R ₁ IR ₂ ) via desulfurization. This was observed through UV-vis absorption and fluorescence emission spectroscopy, with a high fluorescence emission quantum yield (Փ _F = 43-99%) and large Stokes shift (∆v∼115 nm). Furthermore, the DIM probe, which was prepared by treating the DSM probe with ClO ^- , also displayed antibacterial efficacy toward not only Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) but also methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-EC), that is, antibiotic-resistant bacteria. These results suggest that the DSM probe has great potential to carry out the dual roles of a fluorogenic probe and killer of bacteria.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling Editor declared a past coauthorship with one of the authors, JY.
(Copyright © 2021 Pham, Nguyen, Choi, Kim, Jung, Lee, Kim, Lee, Yoon, Kim and Lee.)