Tunable PVA-Alginate/Fe₃O₄ Ferrogels for AMF-Triggered Drug Release and Magnetothermal Hyperthermia

Next-generation drug delivery technologies represent a cornerstone of modern biomedical research, aiming to improve the efficacy, safety, personalization, and sustainability of cancer therapies. In this context, the development of multifunctional ferrogel systems capable of simultaneously enabling controlled drug release and magnetic field-induced hyperthermia is of significant importance. In this study, poly-(vinyl alcohol)-alginate (PVA-Alg)/Fe₃O₄ ferrogels containing 0-2 wt % Fe₃O₄ were successfully fabricated via a combined ionic and physical cross-linking strategy. Comprehensive structural, morphological, and magnetic characterizations were performed using FT-IR, XRD, SEM, TEM, and VSM analyses. The results demonstrate that increasing Fe₃O₄ content significantly reduced the equilibrium swelling ratio (from 72.55 to 18.34 g water/g polymer) and degradation degree (from 46% to 10.3%), while markedly enhancing magnetic saturation (from 0.044 to 28.10 emu/g). Also, the DOX loading capacity decreased from 124 to 76 mg DOX/g polymer due to increased network compactness and reduced availability of active binding sites. Drug release experiments under AMF revealed that both magnetic field strength and Fe₃O₄ loading play a decisive role in regulating release kinetics. The equilibrium drug release values ranged from 62.37 to 95.09 mg DOX/g polymer, accompanied by accelerated release rates under higher magnetic field intensities due to magnetothermal heating effects. Overall, the results indicate that PVA-Alg/Fe₃O₄ ferrogels exhibit tunable structural, magnetic, and drug release properties, highlighting their strong potential as dual-functional platforms for controlled drug delivery and magnetic hyperthermia-based cancer therapy.