Eucalyptus camaldulensis gum as a green matrix to fabrication of zinc and silver nanoparticles: Characterization and novel prospects as antimicrobial and dye-degrading agents

Abstract

Green biosynthesis of nanoparticles (NPs) has gained much significance due to cost-effectiveness, time-efficiency, biocompatibility, and environmentally friendliness. Herein, we report the fabrication of zinc (ZnNPs) and silver nanoparticles (AgNPs) using Eucalyptus camaldulensis (EC) gum extract as a low-cost and green bio-matrix. The as-fabricated EC-ZnNPs and EC-AgNPs were comprehensively characterized by UV–visible spectroscopy, Fourier Transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), and scanning electron microscopy (SEM) techniques. Specific characteristic peaks of synthesized NPs were scrutinized through UV–visible and FTIR. The synthesized NPs revealed irregular shape and size with an increase in roughness of the surface. A delay in the rate of weight loss indicated the stable nature of EC-ZnNPs at high temperatures. Similarly, an increase in the crystallinity nature of EC-ZnNPs and EC-AgNPs was evidenced through XRD analysis. As compared to gum samples, the green fabricated EC-ZnNPs and EC-AgNPs performed an admirable inhibitory activity against a pathogenic bacterium (Escherichia coli) and fungal strain (Schizophyllum commune). Mutagenicity and cytotoxicity activities determined through Ames and haemolytic tests affirmed the non-mutagenic and non-toxic attributes of the gum samples and their derived EC-ZnNPs and EC-AgNPs. Finally, the EC-AgNPs and EC-ZnNPs showed a high photocatalytic potentiality towards the degradation of methylene blue dye under sunlight irradiation. In conclusion, the findings manifest excellent antimicrobial and dye degradation potentialities of gum-based EC-ZnNPs and EC-AgNPs, representing its putative perspective as a novel nano-antibiotic against pathogenic bacterial and fungal isolates, and for environmental mitigation. The present method is eco-friendly, clean and did not require any toxic/hazardous reductants.

Keywords

• Eucalyptus camaldulensis
• Gum polymer
• Green fabrication
• Nanoparticles
• Antimicrobial activity
• Mutagenicity