Facile assembly of Fe3O4@Au nanocomposite particles for dual mode magnetic resonance and computed tomography imaging applicationsElectronic supplementary information (ESI) available: Additional experimental results. See DOI: 10.1039/c2jm16851k

• Main Authors: Cai, Hongdong, Li, Kangan, Shen, Mingwu, Wen, Shihui, Luo, Yu, Peng, Chen, Zhang, Guixiang, Shi, Xiangyang
• Format: Article
• Language: English
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/c2jm16851k

We report a facile approach for fabrication of Fe 3 O 4 @Au nanocomposite particles (NCPs) as a dual mode contrast agent for both magnetic resonance (MR) and computed tomography (CT) imaging applications. In this study, Fe 3 O 4 nanoparticles (NPs) prepared by a controlled coprecipitation approach were used as core particles for subsequent electrostatic layer-by-layer (LbL) assembly of poly(γ-glutamic acid) (PGA) and poly( l -lysine) (PLL) to form PGA/PLL/PGA multilayers, followed by assembly with dendrimer-entrapped gold NPs (Au DENPs) formed using amine-terminated generation 5 poly(amidoamine) dendrimers as templates. After crosslinking the multilayered shell of PGA/PLL/PGA/Au DENPs via EDC chemistry, the remaining amine groups of the outermost layer of Au DENPs were acetylated to neutralize the surface charge of the particles. The formed Fe 3 O 4 @Au NCPs were well characterized via different techniques. We show that the formed Fe 3 O 4 @Au NCPs are colloidally stable, hemocompatible, and biocompatible in the given concentration range (0-100 μg mL −1 ). The relatively high r 2 relaxivity (71.55 mM −1 s −1 ) and enhanced X-ray attenuation property when compared with either the uncoated Fe 3 O 4 NPs or the Au DENPs afford the developed Fe 3 O 4 @Au NCPs with a capacity not only for dual mode CT and MR imaging of cells in vitro , but also for MR imaging of liver and CT imaging of subcutaneous tissue in vivo . With the facile integration of both Fe 3 O 4 NPs and Au DENPs within one particle system via the LbL assembly technique and dendrimer chemistry, it is expected that the fabricated Fe 3 O 4 @Au NCPs may be further modified with multifunctionalities for multi-mode imaging of various biological systems. Fe 3 O 4 @Au nanocomposite particles can be formed via layer-by-layer self-assembly and dendrimer chemistry for dual mode MR and CT imaging applications.