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Recently, a joint research team from the University of Turin, Italy, and the Universitat Politècnica de València, Spain, published an innovative achievement in the journal Journal of Composite Science—the successful development of polylactic acid (PLA) nanofibers loaded with carbon nanoparticles (CNP) and copper-modified carbon nanoparticles (CNP-Cu) via electrospinning machine for food package. This technology not only enhances the antibacterial properties of food packaging but also ensures the safety and environmental sustainability of the materials, providing a new solution for the sustainable packaging industry.
Traditional food packaging materials often face limitations in antibacterial effectiveness, non-degradability, or potential migration risks. The research team used electrospinning device to combine bio-based PLA with carbon nanoparticles, forming an ultra-fine fiber network with diameters of only a few hundred nanometers.
Figure 1: Figure 1. DLS measurements of CNP in different solvents. (A) CNP in water (blue) and in DMF before (black) and after sonication (red). (B) CNP in water (blue) and previously sonicated in DMF and then mixed in 70:30 (v/v) DCM–DMF using DCM values of dynamic viscosity (µ) for the size calculation (black).
By optimizing solvent ratios, voltage, and spinning parameters, the team successfully achieved uniform distribution of nanoparticles within the fibers. Experiments showed that PLA fibers containing 1% CNP-Cu exhibited significant inhibitory effects against common foodborne pathogens (such as Listeria monocytogenes), with mechanical properties of the fibers increased by more than 30%.
Figure 2. FE-SEM images of electrospun neat PLA nanofibers at varying concentrations: 7 wt.% (a), 8.5 wt.% (b), 9 wt.% (c), and 10 wt.% (d).
Addressing public concerns about nanoparticle migration, the research team conducted a 10-day migration test in acidic, alcoholic, and aqueous food simulants, simulating real food contact environments. The results showed that the release of nanoparticles was below the detection limit (5×10⁶ particles/mL), with copper ion migration concentration at only 0.0565 ppm, significantly lower than the EU standard (5 ppm).
Figure 3. FE-SEM images of PLA nanofibers at 10 wt.% in DCM–DMF 70:30 (v/v) and electrospun at different setups. (a) 2.0 mL/h, 20 kV, 12 cm, (b) 2.5 mL/h, 15 kV, 11 cm, (c) 1.5 mL/h, 15 kV, 13 cm, and (d) 2.5 mL/h, 15 kV, 13 cm.
Compared with traditional petroleum-based plastics, PLA is derived from renewable resources such as corn starch and can be completely degraded under industrial composting conditions. The carbon nanoparticles are synthesized from glucose via hydrothermal methods, avoiding dependence on fossil resources.
Figure 4 shows FE-SEM images of both pristine carbon nanoparticles (CNP) and Cu-loaded carbon nanoparticles (CNP-Cu).
The research team also developed a UV-spectroscopy-based rapid detection technology to precisely monitor the loading efficiency of nanoparticles during the production process, paving the way for large-scale production. Currently, this technology is in the pilot verification stage and is expected to be applied in smart labels, antibacterial films, and other scenarios in the future, extending the shelf life of food and reducing the use of preservatives.
Electrospinning Nanofibers Article Source:
https://doi.org/10.3390/jcs9010025
