title: Synthesis variants of quaternary ammonium polyethyleneimine nanoparticles and their antibacterial efficacy in dental materials.
abstract: BACKGROUND
  Resin-based dental materials allow bacterial growth on their surface and lack antibacterial activity, leading to functional and esthetic failure. Quaternary ammonium polyethyleneimine (QPEI) nanoparticles (NPs) incorporated in resin-based composite at 2% wt/wt have demonstrated prolonged and complete inhibition of bacterial growth. This study focused on optimization of QPEI NP synthesis to reduce the concentration required for bacterial growth inhibition. The objective here was to enhance antimicrobial efficacy by excess base neutralization, using phosphoric or hydrochloric acid, and by using surfactants.
  
  
  METHODS
  QPEI NP variants were prepared (i) under controlled neutralization of acid, using NaHCO3, (ii) under controlled carbonate ion neutralization with HCl or H3PO4 and (iii) by treatment with N-lauroylsarcosine or glycerol monostearate. NPs incorporated in the dental materials were examined for their antibacterial effect against Enterococcus faecalis.
  
  
  RESULTS
  Controlled addition of NaHCO3 resulted in modified QPEI NPs with an increased ability to inhibit bacterial growth. Surface treatment with N-lauroylsarcosine resulted in enhanced antibacterial activity at 0.5% wt/wt concentration in acrylate and epoxy resin-based dental materials.
  
  
  CONCLUSIONS
  The antimicrobial efficacy of QPEI NP may be improved significantly by controlling the addition of NaHCO3, neutralization of excess base and the surface-agent effect.
authors.affiliation: Department of Prosthodontics, Hebrew University-Hadassah School of Dental Medicine, Jerusalem - Israel.
authors.forename: Nathan
authors.initials: N
authors.lastname: Zaltsman
authors.affiliation: Department of Prosthodontics, Hebrew University-Hadassah School of Dental Medicine, Jerusalem - Israel.
authors.forename: Dana
authors.initials: D
authors.lastname: Kesler-Shvero
authors.affiliation: Department of Prosthodontics, Hebrew University-Hadassah School of Dental Medicine, Jerusalem - Israel.
authors.forename: Ervin I
authors.initials: EI
authors.lastname: Weiss
authors.affiliation: Department of Prosthodontics, Hebrew University-Hadassah School of Dental Medicine, Jerusalem - Israel.
authors.forename: Nurit
authors.initials: N
authors.lastname: Beyth
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D003764:Dental Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D016984:Enterococcus faecium / Q000254:growth & development*; D053758:Nanoparticles / Q000737:chemistry*; D011094:Polyethyleneimine / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D003764:Dental Materials; D000644:Quaternary Ammonium Compounds; D011094:Polyethyleneimine