Magnetic nanoparticles in MR imaging and drug delivery

Abstract

Magnetic nanoparticles (MNPs) possess unique magnetic properties and the ability to function at the cellular and molecular level of biological interactions making them an attractive platform as contrast agents for magnetic resonance imaging (MRI) and as carriers for drug delivery. Recent advances in nanotechnology have improved the ability to specifically tailor the features and properties of MNPs for these biomedical applications. To better address specific clinical needs, MNPs with higher magnetic moments, non-fouling surfaces, and increased functionalities are now being developed for applications in the detection, diagnosis, and treatment of malignant tumors, cardiovascular disease, and neurological disease. Through the incorporation of highly specific targeting agents and other functional ligands, such as fluorophores and permeation enhancers, the applicability and efficacy of these MNPs have greatly increased. This review provides a background on applications of MNPs as MR imaging contrast agents and as carriers for drug delivery and an overview of the recent developments in this area of research.

The influence of particle size and static magnetic fields on the uptake of magnetic nanoparticles into three dimensional cell‐seeded collagen gel cultures

“…1,2 Within medical and biological research, nanoparticles have widespread applications, ranging from aiding tissue and cell imaging to delivery of therapeutic molecules. 3,4 The use of magnetic nanoparticles (mNPs) in particular, has led to the simultaneous targeting of a specific disease, imaging the site and delivering the required therapy in medical treatment. 5 Magnetic nanoparticles are composed of a metal core with a biocompatible surface coating.…”

In vivo MR quantification of superparamagnetic iron oxide nanoparticle leakage during low‐frequency‐ultrasound‐induced blood–brain barrier opening in swine

“…The contrast agent is then measured directly, and drug delivery is determined based on its concentration on the contrast agent (12,13). The second method assesses therapeutic agent delivery to the brain more accurately, and SPIO nanoparticles have many advantages in this regard: (i) SPIO nanoparticles are biocompatible and can be degraded safely by macrophages/ microglia (14), whereas gadolinium leakage raises safety concerns related to neurotoxicity (15); (ii) SPIO nanoparticle surfaces can be modified to easily conjugate therapeutic agents (12,13); (iii) MRI techniques such as T 2 *-weighted imaging or transverse relaxation rate (R 2 ) maps can be used to quantify the iron concentration in tissues, making quantification of therapeutic agent delivery easier (12,13); (iv) SPIO nanoparticles have high spin-spin relaxivities and can generate high magnetic moments that can be actively manipulated by externally applied magnets, making them suitable for use with magnetic targeting (16,17). The above advantages makes the SPIO nanoparticles has the potential to serve a ''thernostic'' agent, which means that the diagnostic and therapeutic functions can be concurrently provided during drug-delivering process.…”

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

“…[303] Bare MNPs are prone to be attacked by oxidative or corrosive environments in a way that their stability in solution and physiological media can be easily compromised due to their high surface-to-volume ratio. [304] Furthermore, subsequent formation of reactive oxygen species (ROS) will result in loss of magnetic properties of oxidized MNPs on one hand, in a decrease of their biocompatibility on the other hand. [305] Although, magnetite (Fe 3 O 4 ) nanoparticles are highly magnetizable and resistant to oxidation, a loss in their magnetism properties occur once they are oxidized and convert into hematite nanoparticles.…”