PEG-Based Functionalization of Iron Oxide Nanoparticles Using the ISOFURE Methodology

PEG-based Functionalization of Iron Oxide Nanoparticles Using the ISOFURE Methodology

Robert J. Wydra, David S. Spencer, J. Zach Hilt

Department of Chemical and Materials Engineering, University of Kentucky

Magnetic nanoparticles, with their unique physical properties, are being studied for a wide range of biomedical applications such as imaging, targeted delivery, and thermal therapy of cancer.  Surface modification plays an essential role in determining the success of the particles in their application by improving the stability, preventing agglomeration, improving biocompatibility, and providing additional functionality (e.g. targeting antibodies).  Poly(ethylene glycol) (PEG) based functionalization is common for biological applications as a mean to prevent protein adsorption and thus improve the circulation time and minimize host response.  Previous work has investigated using a solution based atom transfer radical polymerization (ATRP) to successfully create PEG-iron oxide core-shell nanoparticles.  In this study, a novel strategy to isolate, functionalize, and subsequently release (ISOFURE) functionalized nanoparticles was harnessed.  Initially iron oxide nanoparticles were synthesized using the facile co-precipitation technique.  The bare particles were entrapped in a biodegradable poly(β-amino ester) (PBAE) hydrogel.  While isolated, the particles were modified with poly(ethylene glycol) (MW=400) dimethacrylate (PEG400DMA) and other monomers using ATRP.  Following the reaction, the PBAE hydrogel network was degraded in water, and the functionalized nanoparticles were collected for characterization.  The particles were characterized using Fourier transform infrared spectroscopy, to verify surface functionalization; thermal gravimetric analysis, to quantify mass percent of coating; dynamic light scattering, to determine particle size; and UV-Vis spectroscopy, to determine particle stability in a variety of media.