In Vitro Antimicrobial Evaluation of Silver Nanoparticles in Lyotropic Liquid Crystals for Cutaneous Wound Treatment

Complex wounds, burns, and diabetic complications increase patients' susceptibility to bacterial infections, which frequently show resistance to standard treatments. This investigation focused on evaluating the antimicrobial potential of lyotropic liquid crystal (LC) formulations loaded with silver nanoparticles (AgNPs) against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli strains. The liquid crystals (LCs) were prepared by incorporating an oily phase (PPG-5-CETETH-20 and oleic acid) into an aqueous phase containing the AgNP nanosuspension. LC-AgNPs formulations, containing AgNPs concentrations between 4.68 μg/mL and 14.04 μg/mL, were examined using polarized light microscopy (PLM), which identified hexagonal, Maltese-cross/lamellar, and dark-field mesophases. The ratio between the aqueous and oily phases directly affected the mechanical, bioadhesive, and rheological properties of the LCs. Over a 24 h period, the formulations released between 1% and 70% of the AgNPs, showing proven efficacy against the tested bacterial strains. The structural features of LC formulations significantly influenced their biocompatibility in L-929 fibroblast cells. The findings demonstrate that LC systems are promising controlled-release platforms for AgNPs, combining antimicrobial activity and biocompatibility for the treatment of bacterial skin infections.