Mesoporous 3D carbon framework encapsulated manganese oxide nanoparticles as biocompatible T-1 MR imaging probe

Abstract

Magnetic resonance imaging (MRI) is one of the widely used medical diagnostic techniques due to its non-invasive nature, higher resolution and efficiency in soft tissue imaging. MRI contrast agents with high relaxivity and biocompatibility are of great importance for successful clinical diagnosis. Manganese based substances have emerged as new class of MR imaging agents due to their impressive contrast ability. In this study, we have reported development of manganese oxide (Mn3O4) nanoparticles encapsulated in mesoporous 3D carbon framework (CF) functionalized by polyethylene glycol (PEG) as T-1 based MRI contrast agent. PEG functionalization endowed solubility and stability of the contrast agent in water which are highly essential traits of MRI contrast agents. The carbon framework provided excellent biocompatibility by ruling out possibility of metal ion exposure (offering suitability for in vivo application) and simultaneously enabled water exchange through its pores which led to T-1 contrast improvement. The as-prepared PEG modified manganese oxide@CF nanosystem exhibited paramagnetic behaviour at room temperature, enhanced water proton relaxation and facilitated contrast of T-1-weighted MR images.