Beta-cyclodextrins conjugated magnetic Fe3O4 colloidal nanoclusters for the loading and release of hydrophobic molecule

Herein, we report a facile method to prepare beta-cyclodextrin ( p-CD)-conjugated magnetic Fe304 colloidal nanocrystal clusters (Fe304@GLY-CD) using (3-glycidyloxypropyl) trimethoxysilane (GLY) as the intermediate linker. The resulting Fe304@GLY-CD was characterized by several methods including Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). In addition, the loading and release properties of the synthesized Fe304@GLY-CD for the hydrophobic molecule 8-anilino-1naphthalenesulfonic acid ammonium salt (ANS) were also investigated. The results show that the Fe304@GLY-CD has a spherical structure with an average diameter of 186 nm and high saturated magnetism of 51.2 emu/g. The grafting of p-CD onto Fe304 colloidal nanocrystal clusters can markedly increase the loading capacity of ANS because of p-CD/ANS inclusion complex formation. The in vitro delivery profile shows that the release of ANS from the Fe304@GLY-CD nanosystem exhibits an initial burst followed by a slow and steady release. Moreover, Fe3 04@GLY-CD also demonstrates a temperaturedependent release behavior for ANS owing to the effect of temperature on the association constants of p-CD/ANS inclusion complexes. The developed magnetic hybrid nanomaterial is expected to find potential applications in several fields including separation science and biomedicine. (C) 2014 Elsevier B.V. All rights reserved.