Iron oxide nanoparticle surface decorated with cRGD peptides for magnetic resonance imaging of brain tumors.

In this article, a specific targeting Magnetic Resonance Imaging (MRI) nanoplatform, composed by iron oxide nanoparticle (NP) with cRGD peptides as targeting agent onto NP surface, is explored for the diagnosis of brain tumors by MRI using intracranial U87MG mice xenograft tumor. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editor: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader.

Antioxidative Theranostic Iron Oxide Nanoparticles toward Brain Tumors Imaging and ROS Production.

Gliomas are the most common primary brain tumor in humans. To date, the only treatment of care consists of surgical removal of the tumor bulk, irradiation, and chemotherapy, finally resulting in a very poor prognosis due to the lack of efficiency in diagnostics. In this context, nanomedicine combining both diagnostic and magnetic resonance imaging (MRI) and therapeutic applications is a relevant strategy referred to theranostic. Magnetic nanoparticles (NP) are excellent MRI contrast agents because of their large magnetic moment, which induces high transverse relaxivity (r2) characteristic and increased susceptibility effect (T2*). NP can be also used for drug delivery by coating their surface with therapeutic molecules. Preliminary in vitro studies show the high potential of caffeic acid (CA), a natural polyphenol, as a promising anticancer drug due to its antioxidant, anti-inflammatory, and antimetastatic properties. In this study, the antioxidative properties of iron oxide NP functionalized with caffeic acid (γFe2O3@CA NP) are investigated in vitro on U87-MG brain cancer cell lines. After intravenous injection of these NP in mice bearing a U87 glioblastoma, a negative contrast enhancement was specifically observed on 11.7 T MRI images in cancerous tissue, demonstrating a passive targeting of the tumor with these nanoplatforms.

Magnetosomes, biogenic magnetic nanomaterials for brain molecular imaging with 17.2 T MRI scanner.

The fast development of sensitive molecular diagnostic tools is currently paving the way for a personalized medicine. A new class of ultrasensitive magnetic resonance imaging (MRI) T2-contrast agents based on magnetosomes, magnetite nanocrystals biomineralized by magnetotactic bacteria, is proposed here. The contrast agents can be injected into the blood circulation and detected in the picomolar range. Purified magnetosomes are water-dispersible and stable within physiological conditions and exhibit at 17.2 T a transverse relaxivity r2 four times higher than commercial ferumoxide. The subsequent gain in sensitivity by T2(*) -weighted imaging at 17.2 T of the mouse brain vasculature is evidenced in vivo after tail vein injection of magnetosomes representing a low dose of iron (20 µmoliron kg(-1)), whereas no such phenomenon with the same dose of ferumoxide is observed. Preclinical studies of human pathologies in animal models will benefit from the combination of high magnetic field MRI with sensitive, low dose, easy-to-produce biocompatible contrast agents derived from bacterial magnetosomes.