Triggering release from thermosensitive polymer gels by magnetic field heating of Fe3O4 nanoparticles

COLL 60

Kimberly Hamad-Schifferli, schiffer@mit.edu, Department of Mechanical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, Room 56-341C, 77 Massachusetts Avenue, Cambridge, MA 02139
Heating of magnetic nanoparticles by magnetic has been utilized for many applications, including cancer therapy, tumor killing, hyperthermia. Its use in drug delivery applications could be particularly useful because administering of the field is possible in a time-controllable manner We describe here use of nanoparticles in heating thermosensitive polymers that undergo dramatic volume changes upon heating. 12 nm Fe3O4 nanoparticles are incorporated into poly N-isopropyl acrylamide along with a molecule to be released, fluorescein dye. We apply alternating magnetic fields and can observe a ~20% volume decrease of the polymer. We also demonstrate release of the dye into the surroundings. Heating characteristics of the nanoparticles in the polymer are quantified, in particular the specific absorption rate (SAR) of the nanoparticles. Effects of varying nanoparticle material and loading are also explored. These results could have significant ramifications on drug delivery in addition to the development of externally controlled polymer actuators.