Resumo:
Chronic wounds represent a biological, psychological, social, and economic burden due to the prolonged treatment and need for continuous care, impacting patients' quality of life and healthcare costs. Infections delay healing and promote the formation of bacterial biofilms, which hinder the action of antibiotics. Alternatives like silver salts can be toxic, and with the emergence of resistant strains, nanotechnology-based therapies, such as liposomes, offer greater efficacy and fewer side effects due to their high biocompatibility, non-toxicity, and ability to protect the drug. In summary, this project aims to prepare liposomes encapsulated with ciprofloxacin, characterize them, and analyze their in vitro antimicrobial and anti-biofilm activity with potential application in wound treatment. The reverse-phase evaporation method was used to prepare the liposomes with a lipid ratio of 75:20:5 of dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC), and distearoylphosphatidylethanolamine-(polyethylene glycol) (DSPE-PEG-2000), respectively. For characterization, tests such as drug encapsulation efficiency, particle size, cytotoxicity, Alamar blue, and fusogenicity were performed. The minimum inhibitory and bactericidal concentration studies were conducted on Gram-positive and Gram-negative bacterial strains, including Staphylococcus aureus, Staphylococcus aureus MRSA - HU25, Escherichia coli, Staphylococcus epidermidis, and Pseudomonas aeruginosa, through the evaluation using Resazurin staining technique and absorbance readings of the plates using a microplate reader. For the anti-biofilm activity study, assays were prepared using the minimum inhibitory concentrations obtained for the bacterial strains, and the techniques used were colony-forming unit counting and scanning and fluorescence microscopy analysis. The prepared liposomes showed an encapsulation efficiency of approximately 29% and an average particle size of 315 nm. The liposomes were found to be non-cytotoxic and fusogenic, while the inhibitory and bactericidal activity results were satisfactory, with efficiency superior to that of the pure drug, and the liposomes’ anti-biofilm activity was observed. These results indicate that the study's objectives were achieved, the liposomes were successfully prepared and characterized, and the inhibitory, bactericidal, and anti-biofilm activity tests were successful. The encapsulated liposomes demonstrated superior activity compared to the isolated drug, highlighting them as a promising alternative for wound treatment.
