Elucidating the Role of Plant Extracts Mediated Gold Nanoparticles as Smart Antimicrobials: Two-Way Attack

Abstract

Pathogenic bacteria remain the primary health concern even after developing a broad spectrum of antibiotics. The emergence of drug-resistant strains increased mortality, perhaps resulting in a never-ending future pandemic. The researchers are currently concentrating their efforts on nanotechnology-based therapies to counteract resistance. The present review focuses on the antimicrobial characteristics of plant-mediated gold nanoparticles (Au NPs). First, the methodology and importance of green synthesis are highlighted. Variability in NPs characterization methods was identified, with dynamic light scattering, zeta potential, and thermogravimetric analysis limited to a few investigations. Second, the Au NPs synthesized using different plant extracts were found to be broad-spectrum antimicrobial agents against Pseudomonas aeruginosa, Escherichia coli, Cryptococcus neoformans, Candida glabrata, Aspergillus niger, etc. The lowest minimum inhibitory concentrations range (1.95–15.62 µg/mL) was observed with Au NPs synthesized using Thymus vulgaris extract against Staphylococcus aureus, P. aeruginosa, Bacillus subtilis, and E. coli. The effect was more pronounced with smaller NPs (<10 nm). The activity of Au NPs might be mediated through a two-way attack which includes nanoparticles’ diverse mechanisms like reactive oxygen species generation, etc., and surface-attached phytocompounds such as flavonoids, alkaloids, phenolics, terpenoids, tannins, etc. The futuristic role of nanotechnology-based interventions in managing microbial infections is imperative. Synergistic interactions of Au NPs with antibiotics, toxicity profiling, stability, and bioavailability could be major areas of NPs research.

Phytofabricated gold nanoparticles as modulators of salt stress responses in spinach: implications for redox homeostasis, biochemical and physiological adaptation

“…In the last few years, numerous research have been done to unravel the role of noble metal NPs in agriculture as a means to enhance crop production and assure food security ( Balkrishna et al., 2023 ; Paulami et al., 2023 ; Thabet and Alqudah, 2024 ). However, phytofabrication of AuNPs, their role in modulating plant responses to abiotic stress, and possible action pathways remain little understood.…”

“… Khan et al., 2020 ; Zafar et al., 2024 ). In specific, gold nanoparticles (AuNPs) has been recognized as the most considered metallic NPs, owing to their stability, resistance to oxidation, antimicrobial characteristics, and low toxicity ( Balkrishna et al., 2023 ; P. V. Noruzi, 2015 ; Kumar et al., 2019 ). Additionally, AuNPs offer synchronized nutrient release, enhancing plant uptake efficiency; therefore, the promotion of AuNPs based nano-formulations has increased in recent times ( Solanki et al., 2015 ).…”

Antimicrobial Hydrogels: Potential Materials for Medical Application

“…However, the cytotoxicity of AuNPs is affected by surface charge, size, shape, and surface modification, and modified AuNPs may be toxic to cells. [ 39 ] The precious metal gold is expensive and costly to use as an antimicrobial agent. The reported gold nanoparticle‐loaded hydrogels are not really considered to be simple to prepare, inexpensive, with long‐lasting antibacterial effect and biodegradability, which are some distance away from the practical application to biomedical aspects and need to continue to study this side.…”