Antimicrobial nanoparticles

Nanoparticles with inherent antimicrobial activity or release antimicrobial species are attractive for incorporation or embedding in polymeric composites for surfaces to obtain self-sterilizing surfaces. Antimicrobial nanoparticles based on common metal oxides or biodegradable organic structures have been used for pharmaceutical and cosmetic applications. Nanoparticles based on metals such as silver and metal oxides have been widely used for various applications, however, these nanoparticles release toxic metal ions and they are consumable. Efforts have been made to synthesize cationic organic nanoparticles that possess long lasting antimicrobial activity by contact without releasing any molecule. Nanoparticles containing quaternary ammonium or cyclopropenium moieties of certain structures have demonstrated strong antimicrobial activity and have been incorporated in dental composites to obtain self-sterilizing surface. N-halamine polymers and nanoparticles releasing active chlorine or bromine have been developed. These rechargeable nanoparticles have been developed for agriculture applications. Organic salts with limited water solubility are effective long acting antimicrobial agents. The synthesis, characterization, biological activity, toxicity and applications will be discussed.