PREPARATION OF ANTIMICROBIAL FILM BASED ON BACTERIAL NANOCELLULOSE AND CARBON QUANTUM DOTS

Carbon quantum dot (CQD) is a new platform of nanomaterials in the range of 1 to 10 nm. This novel material has received extensive attention in the food industry due to its excellent fluorescence properties, high solubility in water, biocompatibility, and antimicrobial properties. In this experimental study, CQD was prepared using black mulberry and its antibacterial activity was evaluated individually and after impregnation in the bacterial nanocellulose (BNC) on Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922.

CQD was fabricated according to a hydrothermal procedure using black mulberry water extract. The size, UV−vis absorption spectrum, FTIR, and antibacterial activity of CQD were examined according to the agar well diffusion method. BNC was prepared from Komagataeibacter xylinus and CQD was added into BNC by ex-situ method and antibacterial properties were then assessed on both pathogens based on an agar diffusion method.

CQDs have narrow size distribution and more than 95% of CQDs were less than 10 nm in size. The diameter zone of inhibition of CQD was 11.9 and 10.2 mm in S. aureus and E. coli, respectively. , Similar results were also obtained after addition of CQD into BNC. Accordingly, BNC films represented potent antibacterial activity on gram-positive bacterium than gram-negative one. Impregnation of CQD in BNC at 30 ºC significantly (p < 0.05) affected the antibacterial activity compared to impregnation at 4 ºC.

Owing to the typical antibacterial and UV−vis absorption spectrum, CQD incorporated BNC has an important capacity for the fabrication of antimicrobial films.