Stability and Relaxation Mechanisms of Citric Acid Coated Magnetite Nanoparticles for Magnetic Hyperthermia

Citations Over TimeTop 10% of 2013 papers

Abstract

Magnetite (Fe3O4) nanoparticles are proper materials for Magnetic Fluid Hyperthermia applications whenever these conjugate stability at physiological (neutral pH) medium and high specific dissipation power. Here, magnetite nanoparticles 9–12 nm in size, electrostatically stabilized by citric acid coating, with hydrodynamic sizes in the range 17–30 nm, and well dispersed in aqueous solution were prepared using a chemical route. The influence of media acidity during the adsorption of citric acid (CA) on the suspension’s long-term stability was systematically investigated. The highest content of nanoparticles in a stable suspension at neutral pH is obtained for coating performed at pH = 4.58, corresponding to the larger amount of CA molecules adsorbed by one carboxylate link. Specific absorption rates (SARs) of various magnetite colloids, determined calorimetrically at a radio frequency field of 265 kHz and field amplitude of 40.1 kA/m, are analyzed in terms of structural and magnetic colloid properties. Larger dipolar interactions lead to larger Néel relaxation times, in some cases larger than Brown relaxation times, which in the present case enhanced magnetic radio frequency heating. The improvement of suspension stability results in a decrease of SAR values, and this decrease is even large in comparison with uncoated magnetite nanoparticles. This fact is related to interactions between particles.

Related Papers

• → Adsorption kinetics of Cd (II) from aqueous solution by magnetite(2011)16 cited
• → Application of magnetite modified with aluminum/silica to adsorb phosphate in aqueous solution(2011)14 cited
• → Synthesis of a stable magnetite (magnetic fluid) colloid solution(2017)4 cited
• → Nuclear magnetic resonance (NMR) relaxation spectroscopy in tissues(1975)24 cited
• → Adsorption of U(VI) from aqueous solution by Triocthylamine (TOA) functionalized magnetite nanoparticles as a novel adsorbent(2014)4 cited