Resumo

Silver nanoparticles have been attracted interest in biomedical engineering because it has excellent antimicrobial properties by killing not only gram-positive but also gram-negative bacteria. Embedding them in a polymer matrix may reduce their cytotoxic effects and can improve their stabilization in aqueous solutions. Noble metal nanoparticles are of considerable analytical interest due to their unique plasmonic properties, which are strongly depending on particle size, shape and aggregation status. Pluronic® F68 forms micelles that are composed of a hydrophobic core and a hydrophilic exterior portion and it can enhance the activity of different antibacterial and antifungal drugs. Furthermore, studies suggest that it has a broad spectrum of biological response - modifying activities. In this way, Pluronic® is one of the most potent drug targeting systems available, which has a remarkable impact on the emergent field of nanomedicine. The aim of this work was to evaluate the influence of Pluronic® F68 on the antimicrobial activity of silver nanoparticles obtained by chemical reduction and previously encapsulated with conventional polymers like polivinilpirrolidone (PVP) and polyvinyl alcohol (PVA). The susceptibly tests were performed using minimal inhibitory concentration method (MIC) against Pseudomonas aeruginosa ATCC 9721, in TSB broth, utilized 24-wells microplate. These experiments were carried out at 37°C during 24 hours. Silver nanoparticles was produced by chemical reaction using silver nitrate reduced in the presence of sodium citrate at 90°C and stabilized using the following polymers (i) PVP, (ii) PVA, (iii) PVP with pluronic and (iv) PVA with pluronic. The results showed that the presence of pluronic promoted a decrease at MIC values for both polymers. To PVA, the MIC values decreased from 12.5% to 6.25% in the condition without and with pluronic, respectively. However, to PVP the necessary amount of nanoparticle to promote the microorganism death was 16 fold higher with pluronic than without it. In this way, pluronic could be a promising enhance agent. But more assays should be delineated with others microorganisms and on near future this combination could be having therapeutic application in medical devices.