Preparation of superparamagnetic Fe ₃ O ₄ nanoparticles from iron sand mediated by soft template and their performance as antibacterial agent

In this work, the soft-template technique was employed in preparing the superparamagnetic Fe ₃ O ₄ nanoparticles from natural iron sand. A series of the Fe ₃ O ₄ nanoparticles formed spinel crystal structure with the particle size in the range of 1.9 to 6.6 nm which was varied by diethylamine concentration as the template. All samples had the functional groups of Fe ³⁺ -O ²⁻ , Fe ²⁺ -O ²⁻ and OH and exhibited the superparamagnetic character. The antibacterial activity of the Fe ₃ O ₄ nanoparticles showed a significant outcome to pathogen growth rate. Pre-administration of bacterial stock solution (E. coli and B. substilis) with magnetite significantly reduced the colony formation compared to control group _. In particular, for Gram-negative bacteria growth rate, pretreat-ment with magnetite declined the colony formation considerably compared to placebo and positive control group. Also, in line with Gram-negative bacteria, the similar pattern of the bacterial killing property was observed in Gram-positive bacteria.