Antimicrobial activity of sulfur nanoparticles: Effect of preparation methods

Sulfur nanoparticles (SNPs) were synthesized using elemental sulfur and sodium sulfide, capped with chitosan as a stabilizer (SNPES), and their properties were compared to SNPs prepared by acidification of sodium thiosulfate (SNPSTS). The SNPs were characterized using UV-visible spectroscopy, EDS, TEM, XRD, and TGA, and their antimicrobial activity was tested using the disk diffusion method and minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) analysis. The SNPES showed a rod-shaped morphology with an average length of 87 nm, while SNPSTS exhibited a spherical shape with an average particle size of 17 nm. The rod-shaped SNPES showed higher thermal stability than the spherical SNPSTS. Both types of SNPs did not show significant antibacterial activity against Gram-negative (E. coli) bacteria but showed significant antibacterial activity against Gram-positive (L. monocytogenes) bacteria. Between the SNPs, SNPES showed higher growth-inhibiting activity against L. monocytogenes than SNPSTS. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of King Saud University.