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.