Carbon dots derived from folic acid as an ultra-succinct smart antimicrobial nanosystem for selective killing of S. aureus and biofilm eradication

Antibacterial and antibiofilm mechanisms of carbon dots: a review

“…Our group found that CQDs prepared with gentamicin had excellent antibiofilm activity at a lower concentration (80 mg mL À1 ), 21 which readily penetrated biofilms compared with the small molecule gentamicin and killed bacteria in biofilms by multiple mechanisms such as the release of ROS, ultimately leading to the complete destruction of biofilms. FA-CDs recently reported by our group were enriched at the site of infection, 63 and their ultra-small size helped them to enter the biofilm and interact with bacterial cells in the deep biofilm. In the acidic environment of the infection site, FA-CDs can gradually increase intracellular ROS levels, disrupt the ROS homeostasis in bacterial organisms, inactivate a variety of proteins, degrade nucleic acids, and disrupt the integrity of cell membranes, thereby destroying the extracellular polymeric material and thus killing bacteria and removing bacterial biofilms.…”

“…4, folic acid carbon dots (FA-CDs) prepared by our group using folic acid as a precursor, had selective antibacterial activity against S. aureus . 63 They were able to accumulate on the cytoplasmic membrane of S. aureus and exhibit excellent oxidase-like and peroxidase-like activities in the acidic environment of the infection site, gradually increasing the intracellular ROS level. At the same time, they can inhibit the activity of superoxide in S. aureus cells, leading to a diminished ability of the bacteria to scavenge excess ROS.…”

“…Furthermore, under photoexcitation, GQDs accelerated the oxidation of non-enzymatic antioxidants and promoted lipid peroxidation, which promoted the phototoxicity of GQDs. Walia et al 61 63 biquaternary ammonium salts as precursors, which interacted with bacterial cell membranes via electrostatic interaction, leading to severe damage and increased permeability of the cell membrane. This further facilitated the penetration of N-CQDs into the cell and induced the production of ROS.…”

“…(B) Fluorescence intensity of intracellular DCF + inside S. aureus. (C) SEM image of normal S. aureus (control) and S. aureus cocultivated with FA-CD 280 (1 mg mL À1 ) for 4 h. Reprinted with permission 63.…”

Recent developments in carbon dots: a biomedical application perspective

“…8a). 72 FA-CDs were employed as a sensitive antibacterial nanoplatform with pH responsiveness. As shown in Fig.…”