title: Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel.
abstract: OBJECTIVE
  The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel) on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa.
  
  
  METHODS
  This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria. The cell morphology of normal and treated bacteria cells was assessed by transmission electron microscopy (TEM), and the effects of S-T-Gel on genome DNA of bacterial cells were evaluated by agarose gel electrophoresis.
  
  
  RESULTS
  S-T-Gel showed promising activity against Staphylococcus aureus and moderate activity against Escherichia coli and Pseudomonas aeruginosa. The observation with TEM suggested that S-T-Gel may destroy the structure of bacterial cell membranes in order to enter the bacterial cell. S-T-Gel then condensed DNA and combined and coagulated with the cytoplasm of the damaged bacteria, resulting in the leakage of the cytoplasmic component and the eventual death of these three bacteria. In addition, the analysis of agarose gel electrophoresis demonstrated that S-T-Gel could increase the decomposability of genome DNA.
  
  
  CONCLUSIONS
  These results about promising antimicrobial activity and mechanism of S-T-Gel may be useful for further research and development in in-vivo studies.
authors: Research and Development Center of Pharmaceutical Engineering, School of Pharmaceutical Sciences, Sun Yatsen University, Guangzhou, China.
authors: Meiwan
authors: M
authors: Chen
authors: Zhiwen
authors: Z
authors: Yang
authors: Hongmei
authors: H
authors: Wu
authors: Xin
authors: X
authors: Pan
authors: Xiaobao
authors: X
authors: Xie
authors: Chuanbin
authors: C
authors: Wu
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000187:drug effects; D004337:Drug Carriers / Q000737:chemistry / Q000494:pharmacology; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000187:drug effects; D005782:Gels / Q000737:chemistry / Q000494:pharmacology*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004337:Drug Carriers; D005782:Gels; D012834:Silver