Amphiphilic Core–Shell Nanocomposite Particles for Enhanced Magnetic Resonance Imaging

Abstract

A scalable synthesis of magnetic core–shell nanocomposite particles, acting as a novel class of magnetic resonance (MR) contrast agents, has been developed. Each nanocomposite particle consists of a biocompatible chitosan shell and a poly(methyl methacrylate) (PMMA) core where multiple aggregated γ‐Fe2O3 nanoparticles are confined within the hydrophobic core. Properties of the nanocomposite particles including their chemical structure, particle size, size distribution, and morphology, as well as crystallinity of the magnetic nanoparticles and magnetic properties were systematically characterized. Their potential application as an MR contrast agent has been evaluated. Results show that the nanocomposite particles have good stability in biological media and very low cytotoxicity in both L929 mouse fibroblasts (normal cells) and HeLa cells (cervical cancer cells). They also exhibited excellent MR imaging performance with a T2 relaxivity of up to 364 mMFe−1 s−1. An in vivo MR test performed on a naked mouse bearing breast tumor indicates that the nanocomposite particles can localize in both normal liver and tumor tissues. These results suggest that the magnetic core–shell nanocomposite particles are an efficient, inexpensive and safe T2‐weighted MR contrast agent for both liver and tumor MR imaging in cancer therapy.

Enhancing MRI through high loading of superparamagnetic nanogels with high sensitivity to the tumor environment

“…On the other hand, the signal intensity of the liver significantly reduced to 15.55% at 1 h and to 14.88% at 4 h. These results suggest that the magnetic nanogels may be suitable for MRI for both the tumor and liver. The enhanced contrast effect could remain for up to 4 h. Thus, the γ-Fe 2 O 3 @PNIPAM/PAm/CTS nanogels may act as a long-lasting contrast agent for diagnosis of tumor and hepatic disease (especially hepatocellular carcinoma 10 ).…”

“…This classication is based on their ability to reduce the signal intensity in T 2 -weighted images, resulting in Paper Nanoscale Advances darker areas or negative contrast. 10,47 Fig. 5B shows the results of signal intensities which were quantitatively analyzed using region of interest (ROI) within the tumor area.…”

“…Negative contrast agents, on the other hand, predominantly consist of superparamagnetic nanoparticles that generate dark images in T 2 -weighted mode. 10 The most commonly used MRI contrast agent in clinical practice is gadopentetate glucosamine (Gd-DTPA), known for its excellent thermodynamic stability and high relaxation rate. 11 However, Gd-DTPA lacks specific distribution in the body.…”

Polymer/iron oxide nanocomposites as magnetic resonance imaging contrast agents: Polymer modulation and probe property control

“…As T 2 CAs with Cs hydrophilic shells, it possessed good stability and biocompatibility under physiological conditions. High T 2 relaxivity (363 Fe mM −1 s −1 , 3.0 T) was nearly 2.4 times higher than SPIONs coated with citrate alone, which could be used for liver‐specific and tumor MRI 131 …”

Theranostic Iron@Gold Core–Shell Nanoparticles for Simultaneous Hyperthermia‐Chemotherapy upon Photo‐Stimulation

“…Additionally, the cytotoxic effects, coupled with rapid clearance by the body, significantly limit the efficiency of chemotherapy. Nanoparticles are extensively used to counter these limitations mainly due to the flexibility in their size which ranges from 1 to 1000 nm, in addition to their different origins, which allows them to be classified into groups such as amphiphilic, polymeric, metallic, inorganic, or biological nanoparticles . The ease of conjugation of nanoparticles to different functional groups has caused the idea of targeted drug delivery to become feasible.…”