Antibacterial activity of citrus-tangerine-peel-extracted carbon dots against gram-negative and gram-positive bacteria

As nanoscale luminescent semiconductors with wide-range access to many precursors, carbon dots (CDs) represent an extremely biofriendly structure with easy and low-cost preparation methods. In the meantime, antibiotic resistance is a global challenge that needs utmost attention for health. In the current study, luminescent CDs were prepared using the solvothermal treatment of<i>citrus tangerine</i>peel-extract. With a bluish excitation-dependent emission, the amorphous CDs include C, O, Ca, and K elements. Biomass-based CDs showed reliable antimicrobial activity against various gram-positive and -negative bacteria. The antibacterial effects of CDs were evaluated and compared with some antibiotics that are routinely used for treatment of infection caused by these bacteria. Our results showed that the antibacterial effects of CDs were more effective than amikacin, gentamycin and ceftazidime in most of the bacterial cultures. It revealed somehow identical properties to that of imipenem, while a little bit worse bactericidal activity compared to ciprofloxacin and cefixime was obtained. In conclusion, the prepared CDs can be an effective alternative for antibiotics, although their side effects in the body have to be investigated.