Poly(acrylic acid) Bridged Gadolinium Metal–Organic Framework–Gold Nanoparticle Composites as Contrast Agents for Computed Tomography and Magnetic Resonance Bimodal Imaging

Abstract

Imaging contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) have received significant attention in the development of techniques for early-stage cancer diagnosis. Gadolinium (Gd) (III), which has seven unpaired electrons and a large magnetic moment, can dramatically influence the water proton relaxation and hence exhibits excellent MRI contrast. On the other hand, gold (Au), which has a high atomic number and high x-ray attenuation coefficient, is an ideal contrast agent candidate for x-ray based CT imaging. Gd metal organic framework (MOF) nanoparticles with tunable size, high Gd (III) loading and multivalency can potentially overcome the limitations of clinically utilized Gd chelate contrast agents. In this work, we report for the first time the integration of GdMOF nanoparticles with gold nanoparticles (AuNPs) for the preparation of a MRI/CT bimodal imaging agent. Highly stable hybrid GdMOF/AuNPs composites have been prepared by using poly(acrylic acid) as a bridge between the GdMOF nanoparticles and AuNPs. The hybrid nanocomposites were then evaluated in MRI and CT imaging. The results revealed high longitudinal relaxivity in MRI and excellent CT imaging performance. Therefore, these GdMOF/AuNPs hybrid nanocomposites potentially provide a new platform for the development of multi-modal imaging probes.

Design and Synthesis of “All‐in‐One” Multifunctional FeS2 Nanoparticles for Magnetic Resonance and Near‐Infrared Imaging Guided Photothermal Therapy of Tumors

“…Currently, three kinds of multifunctional nanomaterials with complex structures have been chiefly developed. The first kind is the mixture containing two or more imaging/therapy agents that are encapsulated/conjugated by organic/polymer molecules, including metal–metal, metal–polymer, polymer–polymer[4a,14] or metal–carbon based blending material . They can simultaneously deliver the multiple of diagnostic and therapeutic functions for tumor, enabling the well detection and treatment effects in a single procedure.…”

Polyelectrolyte-Stabilized Nanotemplates Based on Gd(III) Complexes with Macrocyclic Tetra-1,3-diketones as a Positive MR Contrast Agents

“…Gd(III)‐based nanoparticulate MRI contrast agents are a topic of current interest due to the improved sensing in tissues, which in turn can differentiate normal tissue from diseased tissue and lesions . Gd(III)‐containing nanoparticulate MRI agents are exemplified in literature by crystalline MOFs, GdF 3 , GdPO 4 , [5, 18–20] and Gd 2 O 3 . [6–10, 21–28] Surface hydrophilization is of key importance in colloid stability of the Gd(III)‐based nanoparticles in aqueous solutions.…”

Gold Nanoparticles as X-Ray, CT, and Multimodal Imaging Contrast Agents: Formulation, Targeting, and Methodology

“…PAA acted as the active site to entrap gold particles. The composite particle displayed better MR contrast than clinically available Magnevist at lower concentrations with a similar relaxivity and similar CT attenuation to Omnipaque [120]. G5 PAMAM dendrimers can also be used to entrap other metals for the creation of multimodal particles.…”