Insights into the selective bactericidal activity of W(Mo)Se2 nanosheets for therapy of pathogenic bacterial infections

The abuse and misuse of broad-spectrum antibiotics cause drug resistance in bacteria, which compromises their benefits and thereby increases the demand for new bactericidal mechanisms to reduce the emergence of multidrug-resistant pathogenic bacteria. Herein, ultrathin WSe2 and MoSe2 nanosheets are exfoliated and functionalized with poly(acrylic acid) (PAA) (PAA-WSe2 and PAA-MoSe2) in an aqueous solution as narrow-spectrum or species-specific antibiotics for the treatment of bacterial infections. PAA-WSe2 nanosheets exhibit narrow-spectrum bactericidal activity with low minimum inhibitory concentrations only for gram-positive bacteria, including multidrug-resistant S. aureus, and PAA-MoSe2 displays species-specific antimicrobial activity against S. aureus without external stimuli. Mechanistic studies have revealed that the redox reactions of PAA-WSe2 nanosheets mediated by lipoteichoic acid of gram-positive bacteria to produce a more active element Se4+ are responsible for their narrow-spectrum bactericidal activity against gram-positive bacteria. Finally, the PAA-WSe2 nanosheets effectively eradicate the bacteria in S. aureus-infected mice, leading to excellent therapeutic efficacy in infected wounds. This strategy, based on narrow-spectrum transition metal dichalcogenide antibiotics, can provide an alternative route for the effective treatment of various bacterial infections.