Bioconjugated Thymol-Zinc Oxide Nanocomposite as a Selective and Biocompatible Antibacterial Agent against Staphylococcus Species

Abstract

Owing to the rapid spread of antibiotic resistance among Staphylococcus species, effective and low-risk alternatives to antibiotics are being actively searched. Thymol (THO), the most abundant component of the oil extracted from thyme, can be considered as a natural antibacterial alternative. However, the low antibacterial activity and non-selectivity of THO limit its usage as a universal anti-Staphylococcus agent. Herein, we report the bioconjugation of THO with ZnO nanoparticle (ZO), which resulted in the TZ nanocomposite (NC), as a potent and selective antibacterial agent against Staphylococcus species, particularly S. epidermidis. The cell-free supernatant (CFS) of ATCC 25923 cultures was employed for the production of TZ NC. Successful production of TZ NC was confirmed via X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and ultraviolet–visible (UV–Vis) studies. TZ NC had selective efficacy against Staphylococcus species, with MIC values 2–32-fold lower than THO. The antibacterial mechanisms of TZ NC are proposed to involve membrane rupture, suppression of biofilm formation, and modulation of new cell wall and protein-synthesis-associated cellular pathways. Its biocompatibility against HCT116 cells was also checked. Our findings suggest that the TZ nanocomposite could improve the selectivity and bactericidal activity of THO against target species.

Antibacterial Activity of Zinc Oxide Nanoparticles Loaded with Essential Oils

“…We have previously reported strong antimicrobial activity of chitosan or alginate-based films with ZnO and citronella essential oil [13,67]. The literature also reported some antibacterial nanocomposites with thyme essential oil used in specific applications [81,82]. In addition, some packaging films containing ZnO and cinnamon essential oils have been reported lately [83,84].…”

AMP-Coated TiO2 Doped ZnO Nanomaterials Enhanced Antimicrobial Activity and Efficacy in Otitis Media Treatment by Elevating Hydroxyl Radical Levels

“…[19][20][21][22][23] Inorganic materials such as ZnO and TiO 2 also have limitations such as low selectivity and cytotoxicity, requiring the strategies to enhance their cell selectivity to broaden their application range. 24,25 Antimicrobial peptides (AMPs) are promising antibiotic alternative candidate with excellent selectivity. They possess a positive surface charge, typically ranging from +2 mv to +11 mv.…”

Synthesis, characterization, and antiparasitic effects of zinc oxide nanoparticles-eugenol nanosuspension against Toxoplasma gondii infection

“…Several studies have shown that coating or conjugating ZnO-NPs could improve/enhance their biological functions, biocompatibility, and feasibility for the formulation for in vivo use. ZnO-NPs were coated with curcumin, cinnamaldehyde, thymol, tannic acid, salicylic acid, and others [ [13] , [14] , [15] , [16] ] . The use of ZnO@Eug nanocomposites as dental sealants has been demonstrated in several studies.…”