Combining diagnosis and treatment approaches in one entity is the goal of
theranostics for
cancer therapy. Magnetic nanoparticles have been extensively used as
contrast agents for nuclear magnetic resonance imaging as well as
drug carriers and remote actuation agents. Poly(2-oxazoline)-based polymeric
micelles, which have been shown to efficiently solubilize hydrophobic drugs and
drug combinations, have high loading capacity (above 40% w/w) for
paclitaxel. In this study, we report the development of novel
theranostic system, NanoFerrogels, which is designed to capitalize on the magnetic nanoparticle properties as imaging agents and the poly(2-oxazoline)-based
micelles as
drug loading compartment. We developed six formulations with magnetic nanoparticle content of 0.3%-12% (w/w), with the z-average sizes of 85-130 nm and ξ-potential of 2.7-28.3 mV. The release profiles of
paclitaxel from NanoFerrogels were notably dependent on the degree of
dopamine grafting on poly(2-oxazoline)-based
micelles.
Paclitaxel loaded NanoFerrogels showed efficacy against three
breast cancer lines which was comparable to free
paclitaxel. They also showed improved
tumor and lymph node accumulation and signal reduction in vivo (2.7% in
tumor; 8.5% in lymph node) compared to clinically approved imaging agent
ferumoxytol (FERAHEME®) 24 h after administration. NanoFerrogels responded to super-low frequency alternating current magnetic field (50 kA m-1, 50 Hz) which accelerated drug release from
paclitaxel-loaded NanoFerrogels or caused death of cells loaded with NanoFerrogels. These proof-of-concept experiments demonstrate that NanoFerrogels have potential as remotely actuated
theranostic platform for
cancer diagnosis and treatment.