Abstract:
Zinc oxide (ZnO)-derived materials exhibit unique
antibacterial, antifungal, and photochemical activities and are
widely used in antibacterial formulations. In this work, ZnO
nanosheets were prepared by green and cost-effective synthesis via
a hydrothermal method, and the prepared ZnO nanosheets were
further functionalized with an eco-friendly ionic liquid (IL). Thus,
a sustainable approach was established to synthesize ZnO
nanosheets. The functionalization of ZnO with the synthesized
IL was fully characterized by advanced spectroscopic and
microscopic techniques. The prepared ionic liquid-functionalized
ZnO (IL@ZnO) showed self-organized layered-sheet arrangements caused by the intercalation of the IL onto the surface of
ZnO nanosheets as revealed by scanning electron microscopy
(SEM). The design of the IL comprised a carboxylic acid moiety for functionalization onto the surface of ZnO, whereas the
hydrophobicity was tuned through the incorporation of a long alkyl chain. The developed IL@ZnO material was also tested against
both Gram-positive and Gram-negative pathogenic bacteria for potential antibacterial activity by colony-forming unit (CFU) and
minimum inhibitory concentration tests. The results revealed that the IL@ZnO exhibits significant antibacterial activity against
tested strains. In particular, potent activity was observed against the Gram-positive skin-specific Staphylococcus aureus bacteria strain.
The mechanism of bactericidal activity against bacteria was also explored along with the cytotoxicity toward mammalian cells, which
reveals that the IL@ZnO is nontoxic in nature. To utilize the developed material owing to its bactericidal activity for practical
applications, the IL@ZnO was fabricated onto the surface of cotton fabric, and its surface morphology was examined by SEM; the
activity of IL@ZnO-treated cotton fabric was evaluated by the zone of inhibition assay. Additionally, the IL@ZnO-treated cotton
fabric exhibited remarkable stability along with significant hydrophobicity and breathability and thus can be utilized as a biomaterial
for biomedical applications, especially in medical masks, for reducing the risk of transmission of infectious diseases.
