Abstract: A medical device and an activating method thereof, wherein the medical device is suitable for preventing and/or treating an infection of a skin lesion and includes: (i) a substrate consisting essentially of cellulose, (ii) at least one cationic copolymer obtained by reaction of at least one polyamine, at least one polyamidoamine or a mixture thereof with at least one polyisocyanate, wherein the copolymer is anchored to the substrate, and optionally (iii) at least one dermatologically acceptable amphoteric surfactant.