Faculty of Veterinary Medicine, Urmia University Food Safety and Packaging 3092-7668 1 1 2025 05 15 Green synthesis of carbon dots from onion juice and Ex-Situ embedding for antimicrobial/ultraviolet protective nanocellulose films 24 32 121677 10.30466/fsp.2025.56060.1006 EN Negar Nikfarjam Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Roghayieh Razavi Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University 0000-0002-3835-6710 Mehran Moradi Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University Rahim Molaei Materials Synthesis Laboratory, Carbon Tech Industrial Group, Carbon Tech, Urmia, Iran Journal Article 2025 03 12 Despite the relatively short history of the discovery of carbon dots (C-dots) and the development of their applications, methods for producing nanodots based on green chemistry have consistently attracted the attention of scientists. In this study, green C-dots were synthesized from onion juice using a simple hydrothermal method (200°C, 4 hours), and their optical properties, particle size distribution, and morphology were subsequently evaluated. The antibacterial activity of C-dots was assessed against pathogenic bacteria Escherichia coli (Gram-negative) and Listeria monocytogenes (Gram-positive), with minimum inhibitory concentrations of 8 mg mL-1 and 4 mg mL-1, respectively. Furthermore, the synthesized C-dots were incorporated into nanocellulose using an ex-situ method to produce modified bacterial nanocellulose (BNC) films with both antimicrobial and ultraviolet (UV) protective properties. The carbon dot-embedded nanocellulose demonstrated enhanced UV-blocking capabilities and greater inhibitory activity against Gram-positive bacteria compared to Gram-negative bacteria, highlighting its potential as a promising nano-biomaterial for food packaging applications. https://fsp.urmia.ac.ir/article_121677_d9c471b2988943a6af5d3a32359070cb.pdf