Bioactive Ag(I) coordination complexes as dopants for castor oil plasticized ethylcellulose films

Area of Science:

• Materials Science
• Polymer Chemistry
• Biotechnology

Background:

• Active food packaging aims to extend shelf-life and enhance food safety.
• Ethylcellulose (EC) is a versatile biopolymer for packaging applications.
• Incorporating bioactive agents can impart antimicrobial properties to packaging materials.

Purpose of the Study:

• To develop novel active food packaging films using ethylcellulose, silver (Ag(I)) complexes, and castor oil.
• To evaluate the compatibility and physical properties of the prepared thin films.
• To assess the antibacterial efficacy and silver ion migration of the developed films.

Main Methods:

• Synthesis and characterization of novel Ag(I) acylpyrazolonate complexes with imidazole ligands.
• Preparation of ethylcellulose-based thin films incorporating Ag(I) complexes and castor oil.
• Evaluation of film homogeneity, robustness, and elasticity.
• Antibacterial activity testing against Escherichia coli (E. coli).
• Assessment of Ag(I) ion migration in various food simulants under different conditions.

Main Results:

• The Ag(I) complexes [Ag(QPy,CF3)(Bn-Im)] and [Ag(QPy,CF3)(Bu-Im)] were synthesized and their structures determined.
• Films containing Ag(I) complexes and castor oil showed excellent compatibility, forming homogeneous, robust, and elastic thin films.
• The developed films exhibited enhanced antibacterial activity against E. coli compared to non-plasticized films.
• Very low migration of Ag(I) ions was observed in distilled water, 10% ethanol, and 3% acetic acid.

Conclusions:

• The combination of novel Ag(I) complexes and castor oil in ethylcellulose films creates effective active food packaging materials.
• These films offer significant antibacterial benefits against Gram-negative bacteria like E. coli.
• The low silver ion migration ensures the safety and suitability of these materials for food contact applications.