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 (H2S) related drug-resistant mechanisms represent a growing point in bacteria drug-resistant research. Thereby, novel diagnostic strategies exploration for H2S 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-3H-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 H2S concentration. DPS NP exhibited ratiometric fluorescence alteration from yellow (λem = 553 nm) to blue (λem = 464 nm) due to nucleophilic addition reaction with H2S within five minutes. DPS NP exhibits remarkable capabilities with selectively sensitive colorimetric and ratiometric fluorescent alteration toward H2S over other analytes. Fluorescence microscopy imaging or ratiometric fluorescent visualization for monitoring the concentration of bacterial released H2S 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).