Zein impart hydrophobic and antimicrobial properties to cotton textiles

In this work, zein, a by-product of the agricultural industry of corn, was used to impart hydrophobicity and antimicrobial activity to textiles. The cotton textiles were functionalized with zein in two different forms, free or as particles. The optimized coating conditions which rendered the highest hydrophobic character to the textiles were found to be 50 g/L zein in the free form prepared with 70% ethanol. To enhance the antimicrobial activity of the coated textiles, ellagic acid was encapsulated into the zein particles. These presented stable diameters, between 300 and 450 nm, and positive surface charge revealing high encapsulation efficiency. After textiles coating, the controlled release of ellagic acid was tested against different mimetic biologic solutions. The release profile was dependent on the ethanol concentration, on the sweat solution pH and on the external media used during dialysis. The functionalized textiles revealed differentiated antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). For E. coli the activity was mainly related with the action of zein while for S. aureus a combined effect between the protein and the ellagic acid was observed. The results herein presented pave the way for the development of new zein-based products for a wide range of applications.