Magnetic Field Stimuli-Sensitive Drug Release Using a Magnetic Thermal Seed Coated with Thermal-Responsive Molecularly Imprinted Polymer.

A new stimulus-responsive drug delivery system using Fe3O4 nanoparticles coated with molecularly imprinted polymer (MIP) is reported. Magnetic thermal seeds (MTS) with their size controlled between 10 and 20 nm that could generate heat under an alternate current (AC) magnetic field were modified with a thermal-responsive MIP by grafting polymerization for effective release of an anticancer drug, methotrexate (MTX). The MIP-coated MTS showed the superparamagnetic property as well as the selective adsorption ability toward MTX, and 80% of MXT adsorbed on the MIP-coated MTS was stimulus released at 60 °C by cleaving hydrogen bonding in the recognition sites. Finally, the MTX release from the MTX-loaded MIP-coated MTS under an AC magnetic field within 10 min was successfully demonstrated.