PEG‐Modified NiFe₂O₄ Nanocomposites: Synthesis, Characterization, and Multifunctional Biomedical Applications in Antioxidant, Anti‐Inflammatory, Photoprotective, Antiemolytic, and Antibacterial Therapies

ABSTRACT This study reports the synthesis and characterization of polyethylene glycol (PEG)‐modified NiFe₂O₄ nanocomposite (NiFe₂O₄@PEG NC) using a co‐precipitation method. Characterization techniques, including XRD, confirmed the successful formation of the cubic spinel structure, with crystallite sizes of 18.35 nm for NiFe₂O₄ NC and 20.13 nm for NiFe₂O₄@PEG NC. Optical analysis revealed a reduction in both direct (from 3.78 to 2.72 eV) and indirect (from 1.36 to 1.05 eV) band gaps due to PEG modifying, enhancing light absorption and reducing Urbach energy, indicating improved material quality. The antioxidant activity showed a significant increase in total antioxidant capacity (TAC) from 2.78 to 17.4 μgAA/mg, with moderate DPPH radical scavenging activity increasing from 4.44% to 36.88%. Biological assessments demonstrated strong anti‐inflammatory activity with 78.56% inhibition at 1000 μg/mL, improved photoprotective properties (SPF increased from 8.57 to 21.43), and enhanced antihemolytic activity (inhibition at 100 μg/mL increased to 18.05%). The NCs also exhibited antibacterial activity against several bacterial strains. PEG modifying significantly improved the stability, biocompatibility, and functional properties of the NiFe₂O₄ NCs, making them promising candidates for biomedical applications.