Active antimicrobial compositions, coatings and methods for controlling pathogenic bacteria

The invention relates to novel active antimicrobial compositions, coatings, in particular for wound dressings, and methods for controlling pathogenic bacteria. The present invention uses the fact that pathogenic bacteria secrete cell membrane-lysing and/or cell membrane permeating agents for a responsive system wherein the action of antimicrobial agents is mediated by the presence of pathogenic bacteria itself. According to the present invention biomimetic antimicrobial nanocapsules are provided which have at least one antimicrobial agent encapsulated in a membrane, wherein the nanocapsules are capable to release the antimicrobial agent(s) in response to the presence of any pathogenic bacteria which produce membrane-permeating or membrane-lysing agents. Preferably, the antimicrobial composition of the invention further comprises signalling nanocapsules having at least one type of signalling agent encapsulated in a membrane, and/or wound healing nanocapsules having at least one wound healing agent encapsulated in a membrane, which nanocapsules are also capable to release the respective agent(s) in response to the presence of pathogenic bacteria which produce membrane-permeating or membrane-lysing agents.