Preparation of magnetic nanoparticles functionalized with cross-linked poly(HEMA) via SI-ATRP for controlled delivery of anti-inflammatory drug

Magnetic nanocarriers with tailored properties are of great interest for biomedical applications. In this work, magnetite nanoparticles (Fe₃O₄) were synthesized and modified via surface-initiated ATRP (SI-ATRP) to develop a smart drug delivery platform. The Fe₃O₄ cores were coated with silica and subsequently grafted with a crosslinked copolymer of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate [p(HEMA- co -EGDMA)]. TEM analysisconfirmed the core–shell morphology and uniform coating of the nanoparticles, while VSM demonstrated the preservation of superparamagnetic behavior after surface modification. FT-IR spectra confirmed polymer attachment, thermogravimetric analysis (TGA) revealed significant organic content, and X-ray diffraction (XRD) indicated preservation of the spinel structure. Brunauer–Emmett–Teller (BET) analysis showed a drastic decrease in surface area from 105.72 m²/g for bare Fe₃O₄ to near zero after modification, confirming complete surface coverage. Betamethasone disodium phosphate (BSP), a clinically used water-soluble anti-inflammatory drug, was selected as the model compound. The nanocarriers achieved a loading efficiency of 59%, as verified by UV–Vis spectroscopy. In vitro release studies demonstrated pH-responsive and sustained release up to 98 h, with controlled behavior at physiological (pH 7.2) and mildly acidic (pH 4.7) conditions. MTT assays confirmed good biocompatibility, maintaining >70% cell viability at all tested concentrations. Overall, the fabricated magnetic nanoplatform combines prolonged release, magnetic responsiveness, and biocompatibility, making it a promising candidate for controlled anti-inflammatory drug delivery. • A p(HEMA- co -EGDMA) copolymer was grafted onto Fe₃O₄ nanoparticles via SI-ATRP. • SEM, XRD, and BET analyses confirmed polymer grafting and reduced surface area. • P(HEMA- co -EGDMA) grafted onto Fe₃O₄ was used as magnetic pH-responsive nanocarrier. • The nanocarriers demonstrated high drug loading efficiency and sustained drug release. • Nanocomposites remained magnetic and showed >70% viability in L929 cells.