Drug Repurposing: Unique Carbon Dot Antibacterial Films for Fruit Postharvest Preservation

Area of Science:

• Materials Science
• Food Science
• Biotechnology

Background:

• Fruit spoilage due to oxidation and microbial growth leads to significant food waste.
• Conventional plastics pose environmental concerns, while existing biodegradable films often lack sufficient antimicrobial and antioxidant properties.
• Chitosan films offer biocompatibility and biodegradability but require enhancement for effective food preservation.

Purpose of the Study:

• To develop an environmentally friendly antibacterial film with improved antioxidant and antimicrobial capabilities for food packaging.
• To investigate the potential of carbon dots derived from *Cirsii Herba* (CDs) to enhance chitosan-based films.
• To evaluate the efficacy of the developed film in extending the shelf life of blueberries.

Main Methods:

• Fabrication of a chitosan/carbon dot (CS/G-CDs) composite film using hydrogen bonding interactions.
• Characterization of the carbon dots' structure and the composite film's properties.
• Assessment of antioxidant capacity, antibacterial rate against common foodborne pathogens, and UV shielding effectiveness.
• Evaluation of the film's performance in extending the shelf life of blueberries compared to chitosan films.

Main Results:

• The prepared carbon dots exhibited homogeneous, monodisperse spherical structures.
• The CS/G-CDs film demonstrated a 5.00-fold increase in antioxidant capacity and a 97.0% antibacterial rate.
• The film achieved excellent UV shielding, blocking 99.9% of UVB and 98.2% of UVA radiation.
• Blueberry preservation was extended by 8 days using the CS/G-CDs film compared to the chitosan film.

Conclusions:

• Chinese herb-derived carbon dots significantly enhance the antibacterial and antioxidant properties of chitosan films.
• The developed CS/G-CDs film offers superior UV shielding and extends fruit shelf life, presenting a sustainable packaging solution.
• This approach provides a promising strategy for developing advanced, eco-friendly packaging materials to reduce food waste.