title: Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68.
abstract: BACKGROUND
  Silver nanoparticles (AgNps) have attracted much interest in biomedical engineering, since they have excellent antimicrobial properties. Therefore, AgNps have often been considered for incorporation into medical products for skin pathologies to reduce the risk of contamination. This study aims at evaluating the antimicrobial effectiveness of AgNps stabilized by pluronic™ F68 associated with other polymers such as polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP).
  
  
  METHODS
  AgNps antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method. The action spectrum was evaluated for different polymers associated with pluronic™ F68 against the gram negative bacteria P. aeuroginosa and E. coli and the gram positive bacteria S. Aureus.
  
  
  RESULTS
  AgNps stabilized with PVP or PVA and co-stabilized with pluronic™ F68 are effective against E. coli and P. aeruginosa microorganisms, with MIC values as low as 0.78% of the concentration of the original AgNps dispersion. The antimicrobial action against S. aureus is poor, with MIC values not lower than 25%.
  
  
  CONCLUSIONS
  AgNps stabilized by different polymeric systems have shown improved antimicrobial activity against gram-negative microorganisms in comparison to unstabilized AgNps. Co-stabilization with the bioactive copolymer pluronic™ F68 has further enhanced the antimicrobial effectiveness against both microorganisms. A poor effectiveness has been found against the gram-positive S. aureus microorganism. Future assays are being delineated targeting possible therapeutic applications.
authors.affiliation: Department of Chemical Engineering of the Polytechnic School, University of São Paulo (USP), São Paulo, Brazil. carolinasantos@usp.br
authors.forename: Carolina Alves
authors.initials: CA
authors.lastname: dos Santos
authors.forename: Angela Faustino
authors.initials: AF
authors.lastname: Jozala
authors.forename: Adalberto
authors.initials: A
authors.lastname: Pessoa
authors.forename: Marcelo Martins
authors.initials: MM
authors.lastname: Seckler
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D004355:Drug Stability; D004926:Escherichia coli / Q000187:drug effects; D053768:Metal Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D020442:Poloxamer / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D020442:Poloxamer; D012834:Silver