Transducing magnetism to soft responsive shells: smart nanosystems for magneto-triggered release of ibuprofen

Smart nanocarriers have emerged as powerful platforms for externally controlled drug delivery, enabling precise spatial and temporal regulation of release while minimizing systemic side effects. Ibuprofen (IBU), a hydrophobic nonsteroidal anti-inflammatory drug with low aqueous solubility, particularly benefits from delivery systems that improve stability and bioavailability. In this work, we report on the design, synthesis, and evaluation of a smart hybrid nanosystem (SHN) for magnetically induced thermal release of IBU. The SHN consists of a superparamagnetic iron oxide nanoparticle (SPION) core acting as the magnetic module, a mesoporous silica (SiO^MP ₂) intermediate shell providing drug-loading capacity, surface protection, functional integration, and an outer thermoresponsive poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA) layer enabling remote magneto-actuated temperature-triggered release. Structural and physicochemical characterization by FTIR, TEM, SAXS, and DLS confirmed the successful formation of a well-defined (core@shell)-g-polymer architecture. Magnetization measurements further demonstrated the preservation of superparamagnetic behavior with zero coercivity and a saturation magnetization of approximately 60 emu g^-1. IBU was efficiently loaded into the SHN through a multistep impregnation procedure. In situ release studies performed in tris(hydroxymethyl)aminomethane buffer (pH 7.8) showed pronounced thermoresponsive behavior, with up to 88% of the loaded IBU released at 50 °C, whereas significantly lower release was observed under physiologically relevant conditions. Notably, magnetic field-triggered release was approximately 7-fold greater than conventional thermal release at equivalent experimental times. This enhanced release occurred despite a macroscopic cooling of the dispersion during the radiofrequency magnetic fields experiment, suggesting that localized nanoscale heating at the SPION-polymer interface, rather than bulk heating, is the primary driver of the magneto-thermal transduction mechanism. Overall, these findings demonstrate that (SPION@SiO^MP ₂)-g-PDEGMA SHN represents a promising platform for remotely triggered IBU delivery, combining magnetic responsiveness, controlled release capability, and structural versatility with strong potential for biomedical applications.