One of the most important resistance to antibiotics mechanism displayed by pathogens microorganisms is the growth in biofilms. The biofilm matrix, may act as a barrier limiting the diffusion of antimicrobials, favouring the enzymatic inactivation of antibiotics, or its binding to extracellular polymers. It is currently estimated that more than 60% of the bacterial infections in humans imply the formation of biofilms, such as those from P. aeruginosa mucoid strains in the lung of cystic fibrosis patients.
The ultra-small (< 200 nm diameter) solid lipid nanoparticles (USNA) are highly stable against heat, oxidation, and hydrolytic attacks. Their highly negative Z potential together with an unusual small size are optimal to slide into the biofilm cavities.
USNA are currently being tested to improve the delivery of the antibiotic colistin on the biofilm produced by a mucosa strain of P. aeruginosa.