Antibacterial effect of amino acid–silver complex loaded montmorillonite incorporated in dental acrylic resin

Kumiko Yoshihara, Noriyuki Nagaoka, Aya Umeno, Akinari Sonoda, Hideki Obika, Yasuhiro Yoshida, Bart Van Meerbeek, Yoji Makita

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Several dental materials contain silver for antibacterial effect, however the effect is relatively low. The reason for the lower antibacterial efficacy of silver is considered to be the fact that silver ions bind to chloride ions in saliva. To develop new effective silver antibacterial agents that can be useful in the mouth, we synthesized two novel amino acid (methionine or histidine)–silver complexes (Met or His–Ag) loaded with montmorillonite (Mont) and analyzed their antibacterial efficacy. At first the complexes were characterized using nuclear magnetic resonance (NMR), and amino acid–Ag complex-loaded Mont (amino acid–Ag–Mont) were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antibacterial efficacy of these materials in dental acrylic resin was then investigated by bacterial growth measurement using a spectrophotometer. As controls, commercially available silver-loaded zeolite and silver-zirconium phosphate were also tested. Dental acrylic resin incorporating His–Ag–Mont strongly inhibited Streptococcus mutans growth. This was explained by the fact that His-Ag complex revealed the highest amounts of silver ions in the presence of chloride. The structure of the amino acid–Ag complexes affected the silver ion presence in chloride and the antibacterial efficacy. His–Ag–Mont might be used as antibacterial agents for dental materials.

Original languageEnglish
Article number1442
Issue number6
Publication statusPublished - Mar 2 2021


  • Amino acid
  • Antibacterial
  • Montmorillonite
  • Nuclear magnetic reso-nance
  • Streptococcus mutans
  • X-ray diffraction

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics


Dive into the research topics of 'Antibacterial effect of amino acid–silver complex loaded montmorillonite incorporated in dental acrylic resin'. Together they form a unique fingerprint.

Cite this