Green Synthesis of Multifunctional Carbon Dots with Antibacterial Activities.

Carbon dots (CDs) were obtained from medicinal turmeric leaves () by a facile one-step hydrothermal method and evaluated for their bactericidal activities against two gram-negative; , , and two gram-positive counterparts; , . The CDs exhibited spherical shapes with a mean size of 2.6 nm. The fluorescence spectra of CDs revealed intense fluorescence at λ/ = 362/429 nm with a bright blue color in an aqueous solution. The CDs showed strong photostability under various environmental conditions (pH, salt, and UV-radiation). The complete bactericidal potency of CDs was 0.25 mg/mL for and after 8 h of exposure, while for , and , the CDs at 0.5 mg/mL good antibacterial effect within 8 h and complete eradication after 24 h of exposure is observed. The release of reactive oxygen species played a crucial role in the death of the bacterial cell. The present study provides a strategy for the preparation of CDs from a medicinal plant and their potential antibacterial activities against four common contagious pathogens.