Enhanced antimicrobial efficacy of thermal-reduced silver nanoparticles supported by titanium dioxide

Yen Chi Chen, Kuo Pin Yu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The antimicrobial efficacy of silver nanoparticles (AgNPs) is influenced by many factors, including the particle size, AgNP oxidation state and support materials. In this study, AgNPs are synthesized and supported by two types of TiO2 powders (P25 and Merck TiO2) using two heat-treatment temperatures (120 and 200 °C). The formation of well-dispersed AgNPs with diameters ranging from 3.2 to 5.7 nm was confirmed using transmission electron microscopy. X-ray photoelectron spectroscopy and X-ray diffraction indicated that the majority of the AgNPs were reduced from Ag+ to Ag0 at 200 °C. The AgNP antimicrobial activity was determined by the zone of inhibition against three fungi, A. niger, P. spinulosum and S. chartarum, and two bacteria, E. coli (Gram-negative) and S. epidermidis (Gram-positive). The antimicrobial activity of metallic AgNPs was more pronounced than that of silver nitrate and some antimicrobial drugs. The AgNPs exhibited optimal antimicrobial efficacy when the AgNP dispersion on the surface of TiO2 was in the region between 0.2 and 0.7 μg-Ag/m2. The minimum (critical) AgNP concentrations needed to inhibit the growth of bacteria (E. coli) and fungi (A. niger) were 13.48 and 25.4 μg/mL, respectively. The results indicate that AgNPs/TiO2 nanocomposites are a promising disinfectant against both bacteria and fungi.

Original languageEnglish
Pages (from-to)195-202
Number of pages8
JournalColloids and Surfaces B: Biointerfaces
Volume154
DOIs
StatePublished - 1 Jun 2017

Keywords

  • Antimicrobial efficacy
  • Silver nanoparticles
  • Thermal reduction
  • Titanium dioxide

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