The Effect of Surface Coating of Iron Oxide Nanoparticles on Magnetic Resonance Imaging Relaxivity

Abstract

Iron oxide nanoparticles (IONPs) with acceptable biocompatibility and size-dependent magnetic properties can be used as efficient contrast agents in magnetic resonance imaging (MRI). Herein, we have investigated the impact of particle size and surface coating on the proton relaxivity of IONPs, as well as engineering of small IONPs' surface coating as a strategy for achieving gadolinium-free contrast agents. Accordingly, polymer coating using poly(isobutylene-alt-maleic anhydride) (PMA) with overcoating of the original ligands was applied for providing colloidal stability to originally oleic acid–capped IONPs in aqueous solution. In case of replacement of the original ligand shell, the polymer had been modified with dopamine. Furthermore, the colloidal stability of the polymer-coated IONPs was evaluated in NaCl and bovine serum albumin (BSA) solutions. The results indicate that the polymer-coated IONPs which involved replacement of the original ligands exhibited considerably better colloidal stability and higher proton relaxivity in comparison to polymer-coated IONPs with maintained ligand shell. The highest r2/r1 we obtained was around 300.

Sugar based cationic magnetic core–shell silica nanoparticles for nucleic acid extraction

“…The TGA-DTG curves of NpFeSiIm (gure attached in ESI S7 †) showed a major characteristic decomposition stage at 200 C with a mass loss of 0.88 mg, 15.86%, which could be assigned to the physisorbed water inside the nanoparticle matrix or/and further condensation of the hydroxyl group of silica shell Q 3 (Si(OSi) 3 (OH)) to result in Q 4 (Si(OSi) 4 ). The latter has disappeared aer the fabrication of magnetic nanoparticles with the sugar group since its exposure to reux (heating) condition for two days, which allows the condensation to happen.…”

“…In the last decade, the synthesis of nanoparticles was mainly focused on the application of traditional materials science catalysts, 1 , 2 optical coating, 3 , 4 and ceramics. 5 But in the past few years, due to advancements in the synthesis and characterization of nanomaterials, their application has experienced rapid developments.…”

Immobilization of Horseradish Peroxidase on Magnetite-Alginate Beads to Enable Effective Strong Binding and Enzyme Recycling during Anthraquinone Dyes’ Degradation

“…However, Mag have some limitations in practical application, such as instability (easily oxidized in air), easy agglomeration, problematic distribution and collection [31]. Integrating Mag into other materials to create composite or hybrid materials (e.g., carbon nanotubes with Mag, biopolymers conjugated with Mag) [32][33][34] or coating of Mag with some polymer (e.g., alginate, polyacrylic acid, poly(vinyl alcohol), polyethyleneimine, poly(isobutylenealt-maleic anhydride) polyethylene glycol, starch, methoxypoly(ethylene glycol)) [35][36][37][38][39] are the main strategies used for solving these shortcomings of Mag. Herein, we propose embedding Mag into hydrogel mm-or µm-scale particles (beads) which combine advantages of both (gel particles and Mag)-rapid separation by external magnetic field and/or gravitational settling due to high density, stability against dissolution especially at lower pH of solution, amplified enzyme activity and a number of available methods able to give large amounts of beads under mild and simple preparation conditions.…”

Influence of post-pyrolysis treatment on physicochemical properties and acid medium stability of magnetic carbon nanocomposites

“…To achieve a proper coating of the magnetic core, a wide range of treatments are available, including chemical vapor deposition, solution plasma processing, hydrothermal methods, spray pyrolysis, and solid-phase synthesis [20][21][22]. It has been demonstrated that IONP encapsulation employing different coatings based on citric acid, lactonic acid, polyvinylpyrrolidone, or polyethylene glycol enhances the chemical, thermal, and colloidal stabilities [23,24]. The treatments mentioned above are well known and efficient.…”