Novel and efficient MR active aqueous colloidal Fe(3)O(4) nanoassemblies

Abstract

This work demonstrates a new class of magnetic resonance (MR) active aqueous Fe(3)O(4) magnetic nanoparticle nanoassemblies (Fe(3)O(4) MNNA) of similar to 40 nm size comprising similar to 6 nm particles. They exhibit enhancement in T(2) MR contrast as compared to 6 nm isolated counterparts (Fe(3)O(4) MNP) and commercial contrast agent, ferumoxytol. This significant improvement in the T(2) MR signal arises from the synergistic magnetism of multiple Fe(3)O(4) nanoparticles assembled in Fe(3)O(4) MNNA. These nanoassemblies also show better colloidal stability, higher magnetization, good specific absorption rate (under external AC magnetic field) and cytocompatibility with cells. Further, the functional groups (-NH(2)) present on the surface of Fe(3)O(4) particles can be accessible for routine conjugation of biomolecules through well-developed bioconjugation chemistry. Specifically, a new MR active colloidal amine-functionalized Fe(3)O(4) nanoassembly with enhanced T(2) contrast properties has been fabricated, which can also be used as an effective heating source for hyperthermia treatment of cancer.