Tailoring the antibacterial and antioxidant activities of iron nanoparticles with amino benzoic acid

Abstract

Antibacterial resistance is a massive universal health crisis and one of the most significant threats to human life. Many bacterial species have evolved and obtained resistance against multiple drugs. As a result, alternative antibacterial agents are essentially required to fight infections caused by resistant pathogenic bacteria. To study the antibacterial activity of iron nanoparticles against methicillin-resistant Staphylococcus aureus, the nanoparticles were synthesized via the microwave induced precipitation method using an aqueous solution of ferric and ferrous ions (1 : 1.5) M with sodium hydroxide (3 M). The antibacterial activity of iron nanoparticles was compared with that of copper, zinc, and chromium nanoparticles synthesized via the same approach. UV-Visible spectra show the λ_max of iron nanoparticles at 287 nm. EDX spectra confirmed the absence of impurities; SEM images showed smooth morphology, while XRD diffractions revealed the crystallinity of the particles. The resultant iron nanoparticles were functionalized with p-amino benzoic acid (PABA) and anthranilic acid (AA) to enhance their antibacterial activity. Furthermore, bacteria were grown in the presence of non-functionalized and functionalized iron nanoparticles. The inhibition zones in the disc diffusion assay revealed that all the nanoparticles and alum inhibited the growth of Staphylococcus aureus, notably compared to the control samples. Furthermore, the antibacterial activity of functionalized nanoparticles was compared to that of non-functionalized nanoparticles. The result showed that anthranilic acid-functionalized iron nanoparticles (AA@Fe) are more effective against Gram-positive Staphylococcus aureus than non-functionalized nanoparticles and para-aminobenzoic acid-functionalized iron nanoparticles (PABA@Fe). In contrast to the antibacterial activity, PABA@Fe has a good antioxidant activity compared to AA@Fe.