Tailoring the physico-chemical and antimicrobial properties of agar-based films by in situ formation of Cu-mineral phase

Abstract

New agar-based composite films with increasing Cu-carbonate and Cu-phosphate mineral phase content were prepared by in situ mineralization and solvent casting method. SEM and optical analysis revealed that Cu-carbonate phase had better compatibility with agar matrix than Cu-phosphate phase. Incorporation of both mineral phases improved mechanical and water vapor barrier properties of the obtained mineralized films, in concentration dependent manner. When 5 mM of carbonate precursor was incorporated into agar matrix, mechanical resistance was enchanced for 44% and water vapor barrier property for 40%. The release of Cu (II) was higher in acidic conditions for both mineralized composites and remained in the range of specific release limits for this metal. In addition, both mineralized composite films exhibited distinctive antimicrobial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Overall, the Cu-carbonate and Cu-phosphate mineralized agar films showed potential to be used for food packaging materials, agriculture or medical purposes. © 2019 Elsevier Ltd