Preparation, Characterization, and Antibiofilm Effect of Free and Nanoencapsulated Tetradenia riparia (Hochst) Codd Leaves Essential Oil

Staphylococcus aureus is an important microorganism that has the ability to form biofilm on a various range of surfaces. Factors contributing to the reduction of the effectiveness of the treatment are the development of resistance to antimicrobial drugs. Essential oils (EO) are effective and economical alternatives, however with the disadvantage of rapid oxidation, nanoencapsulation is an alternative that improves stability, reduces toxicity and controls the release of oil. Nanoprecipitation with Poly-lactide was used to obtain nanoparticles (NP) with EO. The antibiofilm effect was observed by the broth microdilution method. A cytotoxic assay was performed using a VERO cell line. Nanoparticles were found to be nanometric, round with regular structures. EO and NP show antibacterial and antibiofilm activity against S. aureus. NP was less cytotoxic than EO.aure Nanoparticle prevented rapid EO evaporation and degradation and enhanced its stability. NP stability was studied using zeta potential. Its value was determined to be around -23.1 mV, which indicates that NP are in fact stable. Melting temperature and melting enthalpy for Blank NP were 54.29 °C and 429.63 J/g. The decreasing in melting enthalpy from 429.63 to 115.83 J/g in NP containing EO makes this system favorable to controlled release of essential oils. NP has a smaller area under the peak, indicating that the EO may modify the crystalline organization, facilitating melting and thus the release of EO. EO and NP presented a growth inhibition of planktonic and biofilm formation against S. aureus. NP were less cytotoxic than free EO. Thus, these findings may contribute to the development of new strategies against infections caused by S. aureus.