Layer-by-layer assembled hyaluronic acid/chitosan-coated Fe3O4@rGO nanoparticles: Synthesis and characterization for doxorubicin delivery in breast cancer cells

Magnetic nanoparticles (MNPs) are of significant interest for biomedical applications, among them, Fe 3 O 4 nanoparticles are widely used. However, they suffer from oxidation and reduced magnetization under physiological conditions. To overcome this limitation, Fe 3 O 4 @rGO (FR) nanoparticles were synthesized via a solvothermal method and optimized for 20 h reaction time. For further functionalization, the MNPs were coated with a multilayered polymeric shell consisted of alternating hyaluronic acid (HA) and chitosan (CHI) layers through a Layer-by-Layer (LbL) assembly method, with doxorubicin (DOX) embedded directly within the HA layers for controlled release, and referred as FR-HC@DOX. In this design, rGO enhances structural stability, HA provides CD44-mediated targeting ability, and CHI improves biocompatibility. The LbL technique allows for precise control of coating thickness and uniform layer deposition enhancing drug-loading efficiency and ensuring controllable release profiles. The optimized FR-HC@DOX maintained sufficient magnetic response (M s = 26.04 emu/g) after drug loading, which is substantially higher than most reported polymer-coated Fe 3 O 4 systems that typically drop below 20 emu/g. This magnetic nanocarriers also exhibited strong pH sensitivity (∼100% release at pH 5.5 vs 13% at pH 7.4) and showed potent anticancer activity in MCF-7 cells while remaining biocompatibility in MCF-12A healthy control cells at concentrations up to 80 μg/mL. This study presents a new approach by combining rGO embedded/coated Fe 3 O 4 with multilayer HA/CHI coatings, creating a magnetic nanocarrier that improves the stability of Fe 3 O 4 , controllable, pH-responsive and targeted drug release. These results position the system as a distinctive and effective nanoplatform for magnetically guided, tumor-targeted chemotherapy.