Effect of silica on the ZnS nanoparticles for stable and sustainable antibacterial application

Abstract

AbstractSilica‐capped Zinc Sulfide (ZnS) nanoparticles were synthesized for the use as stable and long‐term antibacterial agents because silica is a very important component in food packaging applications for moisture absorption in tune with its property of biocompatibility and water solubility. The variation in morphological and optical properties of core‐shell nanostructures was studied by changing the concentration of silica in a core‐shell combination. The structural and morphological properties of silica‐capped ZnS have been observed by powder X‐ray diffraction (PXRD) and transmission electron microscopic (TEM) studies, respectively. Uncapped ZnS nanoparticles with particle size of 2‐4 nm in a highly agglomerated state have been observed from TEM, which shows that they can be used only for short‐term antibacterial action despite its excellent zone of inhibition (antibiotic sensitivity). However, ZnS/SiO2 core‐shell nanostructures are highly monodisperse in nature and the particle size increases up to 5‐8 nm with increase in silica concentration. Fourier‐transform infrared spectroscopy (FTIR) analysis confirms the formation of silica capping on the ZnS surface. The inhibition of defect‐related emission by silica capping in energy‐resolved photoluminescence studies also shows the formation of very stable ZnS nanoparticles. To study the antibacterial properties of the pure and silica‐capped ZnS nanostructure the agar‐well diffusion method was employed against both gram‐positive and gram‐negative bacteria. The obtained results indicate that pure ZnS shows excellent antibacterial action but it can last only for few days.