Fe3O4@SiO2/Schiff-base/Zn (II) nanocomposite functioning as a versatile antimicrobial agent against bacterial and fungal pathogens

Abstract

Antimicrobial resistance (AMR) presents a critical global health issue, necessitating novel therapeutic strategies to manage bacterial and fungal infections. This study explores the development and evaluation of multifunctional Fe₃O₄@SiO₂/Schiff-base/Zn (II) magnetic nanocomposite (MNC) with enhanced antimicrobial properties. The synthesized MNC combines the magnetic characteristics of Fe₃O₄ magnetic nanoparticles (MNPs) with the antimicrobial properties of Schiff-base ligand functionalized with Zn (II) ions. The preparation involved the coprecipitation of Fe₃O₄, coating with SiO₂ via a modified Stöber method, and subsequent functionalization with Schiff-base/Zn (II) complex. Comprehensive characterization using FT-IR, XRD, SEM, TEM, DLS, EDX, VSM, and TGA confirmed successful synthesis, structural integrity, and superparamagnetic behavior of the MNPs and MNC. The antifungal and antibacterial activities were assessed against six Candida species and four bacterial strains using broth microdilution methods. The Fe₃O₄@SiO₂/Schiff-base/Zn (II) MNC exhibited significant inhibitory effects, with MIC values of 8-64 µg/mL for Candida species and 64-512 µg/mL for bacteria, demonstrating potent antimicrobial efficacy. The MTT assay indicated biocompatibility across various concentrations, except for slight cytotoxicity at 256 µg/mL after five days. To our knowledge, this is the first report integrating Zn (II) Schiff-base ligands into magnetic nanoparticles to achieve a versatile platform for both antimicrobial and biofilm inhibition applications.