Magnetically triggered drug release from biocompatible microcapsules for potential cancer therapeutics

This paper demonstrates that magnetic field triggered drug release from magnetic lipid microcapsules (MLMs) in a controlled manner. Two types of MLMs were fabricated, i.e., MLMs with negatively charged magnetic nanoparticles (MNPs) inside and MLMs with positively charged MNPs on their surfaces. The release of carboxyfluorescein (CF) and the chemotherapy drug doxorubicin (Dox) induced by the AC magnetic field (AMF) was investigated in detail both experimentally and theoretically. Although the drug release of these two types of MLMs synchronizes the switch of the AMF, they exhibited different mechanisms. The magnetic heating effect dominates the release of MLMs with MNPs inside, while both magnetic heating and oscillation effects play important roles in the release of MLMs with MNPs on the surfaces. The in vitro cytotoxicity experiments of Dox loaded microcapsules toward HeLa cells were further performed, which confirmed that these magnetic responsive drug carriers had obvious effects on cell death triggered by the external non-invasive AMF.