Synthesis, Electrochemical Studies, and Antimicrobial Properties of Fe₃O₄ Nanoparticles from <i>Callistemon</i> v<i>iminalis</i> Plant Extracts

• Main Authors: Gloria E. Uwaya, Omolola E. Fayemi, El-Sayed M. Sherif, Harri Junaedi, Eno E. Ebenso
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Materials
• Subjects: green-mediated; Fe3O4-NP; callistemon viminalis; characterization; cyclic voltammetry; antimicrobial activity
• Online Access: https://www.mdpi.com/1996-1944/13/21/4894

Less toxic, environmentally safe green-mediated iron (III) oxide nanoparticles (Fe₃O₄-NP) synthesized using <i>Callistemon viminalis</i> (<i>C. viminalis</i>) leaf (Fe₃O₄-NPL) and flower (Fe₃O₄-NPF) extracts is reported in this work for the first time. Total flavonoids and phenols present in the plant extracts were determined. Characterization of the nanoparticles was carried out using Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible spectroscopy (UV–VIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Malvern zeta sizer. Other properties of the nanoparticles were investigated using the thermogravimetric analyser and cyclic voltammetry. The average particle sizes obtained for Fe₃O₄-NPL and Fe₃O₄-NPF were 17.91 nm and 27.93 nm, respectively. Fe₃O₄-NPL exhibited an excellent electrochemical activity when compared with Fe₃O₄-NPF based on a stability study using cyclic voltammetry and regression value. Additionally, Fe₃O₄-NPF displayed excellent antimicrobial activity against <i>Bacillus cereus</i>, <i>Salmonella enteritidis</i>, and <i>Vibrio cholerae</i> with zones of inhibition of 13, 15, and 25 mm, respectively. Simple, cheap, and less toxic green-mediated iron (III) oxide nanoparticles synthesized from <i>C. viminalis</i> leaf (Fe₃O₄-NPL) and flower (Fe₃O₄-NPF) extracts hold the potential of being used to control the activity of pathogenic bacteria of health importance and as an electrochemical sensor for both biological and environmental analytes.