Molecular Imaging Contrast Properties of Fe3O4‐Au Hybrid Nanoparticles for Dual‐Mode MR/CT Imaging Applications

Abstract

AbstractThe development of noninvasive testing techniques in medicine by combining dual‐mode Magnetic Resonance (MR)/ Computed Tomography (CT) imaging techniques will help overcome the limitations of the separated methods, leading to more accurate diagnoses. This has implications in clinical research, but currently remains a major challenge in terms of the need for a corresponding multimodal signal contrast agent. In this study, we use small size, monodispersed Fe3O4 magnetic nanoparticles as the seeds to synthesize magneto‐plasmonic Fe3O4@Au hybrid nanoparticles (HNPs) with multiple functions with core‐shell structures. The influence of the ratios of HAuCl4 and oleyamine (OLA) precursors on the shape and size of the nanoparticles (NPs) was investigated. The HAuCl4/OLA ratio of 0.2/1 is the optimal condition. The obtained NPs has an average size of 21.2 nm with a uniform spherical shape, high monodispersity. After the surface functionalization with poly(acrylic acid) (PAA), the resulting Fe3O4@Au@PAA HNPs showed excellent dispersion in water, good biocompatibility, non‐toxicity against Hep‐G2 cancer cell line and Vero healthy cell line at high test concentration. The In‐vitro test data showed that the materials with Au shell enhance X‐ray decrease even at low concentrations compared to iodine‐based commercial substances while retaining the same effect as T2 contrast agent with high transverse relaxation rate r2 (125.2 mM−1s−1). The In‐vivo MRI images of rat liver tissue demonstrated that the hybrid nanoparticles showed the contrast increases 3 times under 1.5 T magnetic field after 30 minutes of drug administration. The computed tomography measurements showed the highest Hounsfield unit (HU) of 133.5 after the hybrid nanoparticle injected for 30 minutes. The in‐vivo efficacy of Fe3O4@Au@PAA magneto‐plasmonic hybrid nanoparticles was further evaluated in the cardiac and renal organs in a mouse test model to study drug kinetics. Generally, these Fe3O4@Au@PAA hybrid nanomaterials showed great promise as a candidate for multi‐modality molecular bio‐imaging.