Ratiometric fluorescent nanoprobe for imaging and screening of hydrogen sulfide related bacterial resistance

As a metabolite or reductive cytoprotective gas of bacteria to mediate and mitigate the oxidative stress imposed by antibiotics, hydrogen sulfide (H 2 S) related drug-resistant mechanisms represent a growing point in bacteria drug-resistant research. Thereby, novel diagnostic strategies exploration for H 2 S related drug-resistant pathways recognition are important for drug-resistant bacteria monitoring. Herein, a new organic fluorescent dye ( E )− 3-(3,3-dimethyl-2-styryl-3 H -benzo[ f ]indol-1-ium-1-yl) propane-1-sulfonate self-assembled nanoprobe (DPS NP, ~200 nm) was designed for ratiometric fluorescent monitoring the change of H 2 S concentration. DPS NP exhibited ratiometric fluorescence alteration from yellow (λ em = 553 nm) to blue (λ em = 464 nm) due to nucleophilic addition reaction with H 2 S within five minutes. DPS NP exhibits remarkable capabilities with selectively sensitive colorimetric and ratiometric fluorescent alteration toward H 2 S over other analytes. Fluorescence microscopy imaging or ratiometric fluorescent visualization for monitoring the concentration of bacterial released H 2 S show DPS NP can act as particular diagnostic technique for screening of β -lactam antibiotic resistance in Methicillin-resistant Staphylococcus aureus (MRSA) and nonresistant bacteria Staphylococcus aureus ( S. aureus ) .