Modified cotton gauze with nano-Ag decorated alginate microcapsules and chitosan loaded with PVP-I

This study was aimed at improving the conventional cotton gauze for achieving advanced wound dressing specifications. Firstly, microcapsules of alginate (Alg-MC) were formed and silver nanoparticles (AgNPs) were synthesized in situ inside (Method I: Ag/Alg-MC) or on (Method II: Ag@Alg-MC) Alg-MC. A solution of chitosan (CS) containing already prepared povidone-iodine (PVP-I) was loaded with Ag/Alg-MC or with Ag@Alg-MC. Finally, conventional cotton gauze substrate was impregnated with these two prepared dispersions and dried. Both samples showed antibacterial properties against gram-negative (Escherichia coli) and gram-positive bacterium (Staphylococcus aureus). Their water absorbency, water holding capacity, and vertical wicking increased by 55, 28, and 33%, respectively, in comparison with the control sample. Ag@Alg-MC showed burst release in comparison with Ag/Alg-MC. The conventional properties of cotton gauze were greatly improved by the introduced method and it was regarded as a proper candidate for application as an advanced wound dress.