Healthcare-associated infections are a major problem in hospitals and health care
facilities, mostly caused by bacteria such as Staphylococcus aureus. These infections are often
related with biofilm formation onto surface of medical devices such as catheters. Due to this
fact, the need to find strategies for prevention is emergent and required. A possible alternative
is the use of the biosurfactants sophorolipids that present antimicrobial activity and the ability
to prevent biofilm formation. If a more prolonged antimicrobial effect is desired,
encapsulation of sophorolipids into nanoparticles can be a promising approach.
The aim of this study was the encapsulation of sophorolipids into chitosan nanoparticles
by ionic gelation to obtain antimicrobial particles intended for the prevention of biofilm
formation. The antimicrobial activity was evaluated by the broth microdilution method and
biofilm production was observed through scanning electron microscopy.
Nanoparticles containing sophorolipids were produced in a small scale approach and
incorporation of active compounds was successfully achieved. Within the different
concentrations tested, it was the 3.75 mg mL-1 concentration of sophorolipids that the highest
mass of active compounds was incorporated into the particles. Scale-up production was
performed with an encapsulation efficiency of 11.2 %. The minimum inhibitory concentration
of these particles able to inhibit Staphylococcus aureus growth was ≥ 40 mg mL-1. From scanning electron microscopy observation of nanoparticlesfunctionalized silicone rubber discs, it was possible to notice a reduction in biofilm formation in these specimens when compared to the ones functionalized without active compound loaded nanoparticles.
In conclusion, the results of this study revealed that sophorolipids incorporated in
nanoparticles diminished biofilm formation and might be a possible approach for a prolonged
effect on medical catheters.