Facile synthetic route to Fe3O4/silica nanocomposites pillared clay through cationic surfactant-aliphatic acid mixed system and application for magnetically controlled drug release

• The magnetic porous clay with ordered interlayered meospores were synthesized.
• The synthetic route using mixed cationic surfactant-aliphatic acid system was established.
• The mainly magnetic oxides Fe3O4 were incorporated into silica framework in high dispersion.
• The synthesized magnetic silica-pillared clay exhibit superparamagnetic behavior at room temperature.
• The obtained magnetic SPC has a strong magnetization response.

The clay minerals have received considerable attention because of their environmental compatibility, low cost, high selectivity, reusability and operational simplicity. This article describes a new synthetic route to magnetic silica-pillared clay (SPC) composites through cationic surfactant-aliphatic acid mixed system method. The magnetic nanoparticles generated onto the silica-pillared clay host is mainly composed of Fe3O4, and such self-assembly process of SiO2–Fe3O4 magnetic nanoparticles occurs in the interlayered regions of layered clay. The formed magnetic silica-pillared clay keeps the ordered layered structure and uniform gallery pore size. The effect of varying added Fe source and oleic acid on the synthetic process has been studied experimentally. The results indicate that oleic acid plays a key role in Fe3O4 dispersion. The formed organic (C18H35COO)3Fe and (C18H35COO)2Fe could homogeneously dispersed in the intercalated compounds and formed C18H35COONH4 cooperating with cationic surfactants effects ordered and stable interlayered mixed micelles. Such process ensures the interlayered nano-sized magnetic particles formed with high dispersion and ordered mesoporous structure conserved. The in vitro drug release rate of the magnetic SPC loading ibuprofen was also studied on detail. Under an external magnetic field of 0.15 T, the drug release rate of the magnetic SPC composites decreases dramatically owing to the aggregation of the magnetic SPC composites' particles triggered by non-contact magnetic force. Additionally, the obtained magnetic SPC has a strong magnetization response, implying the possibility of application in magnetic drug targeting.

The relative drug release rates of the iron@SPC-2 under repeated MF on-off operations.Figure optionsDownload as PowerPoint slide