Green synthesis of iron oxide nanoparticles usingCeratonia siliqua L.aqueous extract: improvement of colloidal stability by optimizing synthesis parameters, and evaluation of antibacterial activity against Gram-positive and Gram-negative bacteria

Abstract

This study focused on the colloidal stability enhancement of iron oxide nanoparticles synthesized using aqueous extract of the Ceratonia siliqua L. (carob pod) by optimizing the synthesis parameters. The synthesis parameters were determined as the concentration of iron ions, the concentration of extract, pH of extract, temperature, stirring rate, and reaction time. The significance of the studied factors in controlling the particle size distribution of nanoparticles was quantitatively evaluated via analysis of variance (ANOVA). Iron oxide nanoparticles were produced with an average zeta potential of +41 ± 0.8 mV, hydrodynamic size of 78 ± 22 nm, and a polydispersity value of 0.42 ± 0.06, respectively. As a result of the stability study by measuring the zeta potential, it was determined that the colloidal stability was maintained for 3 months. Green iron oxide nanoparticles (gIONPs) showed inhibition zones of 24.27 ± 0.12 mm and 20.83 ± 0.11 mm in 250 mg/mL concentration against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial strains, respectively. S. aureus was susceptible to the gIONPs according to the standard antibiotics of Cefotaxime (≥23 mm), Tetracycline (≥19 mm), Gentamicin (≥15 mm), and Cefoxitin (≥22 mm). E. coli was susceptible to the gIONPs according to the standard antibiotics of Tetracycline (≥19 mm) and Gentamicin (≥15 mm), but showed resistance to the Cefotaxime (15–22 mm) and Cefoxitin (≤21 mm) standard antibiotics. This study suggests that the green synthesized iron oxide nanoparticles could be used as an antimicrobial agent and a promising candidate for usage in sensor, biomedical, and electronics applications for being in a highly stable structure.

Implication of Iron Oxide Nanoparticles Synthesized using Fruit Peel Extract as Antioxidant Agent and Catalytic Degradation

“…The stability of NPs arises due to the electrostatic repulsion among the particles. 68,69 Figure 10 exhibited the typical FTIR spectrum of synthesized iron oxide nanoparticles which displays modes, typical of organic groups (biomolecules) and Fe-O in both Punica Granatum and Artocarpus Heterophyllus extract solution. Peak at 3251.16 cm −1 and 3247.05 cm −1 (Fig.…”

Iron Oxide Nanoparticles: Green Synthesis and Their Antimicrobial Activity

“…The surface charge is the charge formed on the surface of the nanoparticle as a result of proton adsorption or desorption at hydroxylated sites, and due to the difficulties of directly measuring this charge, the particle's zeta potential is frequently determined. The zeta potential (ζ) is the difference in potential between the stationary layer of the dispersion medium attached to the dispersed particle and the mobile dispersion medium [195] and can be measured by titration [196] or electrophoresis [119,197,198]. It is important because it is used as an indicator of colloidal stability, which is a critical parameter for many emulsions or dispersions.…”

“…As mentioned above, the solution's ionic strength and pH heavily influence the diffusion potential [204]. Therefore, modifying these parameters and others, such as temperature, surface coating of IONP, or concentration variations, can substantially impact the IONP stability [197].…”

“…Due to the amphoteric character of these hydroxyls, the nanoparticles may react with both acids and bases, and the IONP's surface can be positive or negative, depending on the pH of the solution. The isoelectric point is at pH 6.8; around this point, the surface charge density is too low, causing the particles to flocculate [197,204]. It is interesting to note that adding an acetate buffer (pH = 3) can stabilize and prevent the aggregation of amorphous IONP produced from an H. vulgare plant extract (pH = 5.8).…”

Evaluation of Free Radical Scavenging and Antimicrobial Activity of Coleus amboinicus-Mediated Iron Oxide Nanoparticles

“…In the study and advancement of materials science and technology, the green synthesis technique is an effective synthesis process [3]. The reduction of waste, the use of safer solvents and renewable feedstock, as well as the reduction of pollutant derivatives, are some fundamental concepts of "green synthesis" [4]. Metal oxide nanoparticles have been identified as a promising alternative when addressing microbial resistance to antibiotics since they have lower toxicity, higher stability, more selectivity, and greater endurance than organic nanomaterials [5].…”