Green and Economic Fabrication of Zinc Oxide (ZnO) Nanorods as a Broadband UV Blocker and Antimicrobial Agent

Abstract

Zinc oxide (ZnO) nanoparticles have gained widespread interest due to their unique properties, making them suitable for a range of applications. Several methods for their production are available, and of these, controlled synthesis techniques are particularly favourable. Large-scale culturing of Chlorella vulgaris produces secretory carbohydrates as a waste product, which have been shown to play an important role in directing the particle size and morphology of nanoparticles. In this investigation, ZnO nanorods were produced through a controlled synthesis approach using secretory carbohydrates from C. vulgaris, which presents a cost-effective and sustainable alternative to the existing techniques. Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD) analysis, transmission electron microscopy (TEM), and UV-Vis spectroscopy were used to characterise the nanorods. The prepared nanorods exhibited a broad range of UV absorption, which suggests that the particles are a promising broadband sun blocker and are likely to be effective for the fabrication of sunscreens with protection against both UVB (290–320 nm) and UVA (320–400 nm) radiations. The antimicrobial activity of the prepared nanorods against Gram-positive and Gram-negative bacteria was also assessed. The nanostructures had a crystalline structure and rod-like appearance, with an average length and width of 150 nm and 21 nm, respectively. The nanorods also demonstrated notable antibacterial activity, and 250 μg/mL was determined to be the most effective concentration. The antibacterial properties of the ZnO nanorods suggest its suitability for a range of antimicrobial uses, such as in the food industry and for various biomedical applications.

Green Synthesis of Zinc Oxide Nanoparticles (ZnO-NPs) Using Arthrospira platensis (Class: Cyanophyceae) and Evaluation of their Biomedical Activities

“…The toxicity of ZnO-NPs can be attributed to the generation of reactive oxygen species (ROS), the release of Zn (Zn 2+ ) ions inside the microbes, and the change in cell wall permeability [ 63 ]. The generation of ROS is considered the major reason for nanotoxicity which involved the damage of cellular components (proteins, lipid, nucleic acid, phospholipid, amino acids) [ 61 ].…”

Antimicrobial Activity of Zinc Oxide Nano/Microparticles and Their Combinations against Pathogenic Microorganisms for Biomedical Applications: From Physicochemical Characteristics to Pharmacological Aspects

“…These NPs were synthesized by the precipitation method using 2-mercaptoethanol as a capping agent. Tahizdeh et al [ 100 ] reported that ZnO nanorods at an MIC of 250 μg/mL had antimicrobial activity against E. coli , P. aeruginosa , S. aureus , and Enterococcus faecalis, excluding E. faecalis which was resistant to ZnO nanorods. These nanorods were small crystals 3.4 nm in size and the NPs were 150 nm in length and 21 nm in width (aspect ratio, 7.14).…”

Anisotropic transition metal–based nanomaterials for biomedical applications

“…fabricated the ZnO nanorods by controlled synthesis using secreted carbohydrates of Chlorella vulgaris . [ 105 ] In this study, the antibacterial ability of ZnO nanorods was also demonstrated.…”