Stable and Monodisperse Iron Nitride Nanoparticle Suspension for Magnetic Diagnosis and Treatment: Development of Synthesis and Surface Functionalization Strategies

Abstract

The past decade has seen tremendous progress in the synthesis and surface functionalization of iron oxide nanoparticles (IONPs) for a variety of biomedical applications. However, there is still a growing demand on magnetic nanoparticles with higher magnetic moments for more sensitive diagnosis and lower dose treatments in magnetic bioassays, imaging, and therapies. In view of this need, the γ′-Fe 4 N nanoparticle, with around 3 times higher saturation magnetizations than IONPs, becomes one promising alternative for these applications. However, the large and non-uniformly distributed sizes of γ′-Fe 4 N nanoparticles hinder the biomedical applications. These synthesized γ′-Fe 4 N nanoparticles are not suitable for biomedical applications at the current stage. Herein, we have developed and demonstrated a wet ball milling method along with different surface-active media to produce ultrastable, monodispersed, uniformly sized, and sub-100 nm γ′-Fe 4 N nanoparticles in solvents. Different standard characterization methods such as transmission electron microscopy, nanoparticle tracking analysis, and Fourier-transform infrared spectroscopy are carried out to measure the physicochemical properties of these surface-functionalized γ′-Fe 4 N nanoparticles. It is confirmed that the functional chemical groups have been successfully anchored on our purified sub-100 nm γ′-Fe 4 N nanoparticles, which allows for convenient subsequent conjugation of proteins, nucleic acids, and drugs for future in vitro and in vivo biomedical applications.

Magnetic nanoparticles and magnetic particle spectroscopy-based bioassays: a 15 year recap

“…One is milling without surfactants, called dry milling, and the other is milling with surfactants, called wet milling. A surfactant, such as heptane, oleic acid, etc, is adsorbed on the new surfaces of particles peeled off from the bulk material during the milling process [126][127][128]. Then, the fresh surfaces of the new particles are separated by layers of surfactant, which can help decrease the welding effect of small particles to obtain nanoparticles with smaller sizes.…”

“…The size distribution of nanoparticles synthesized by this method is usually very wide. A narrower size distribution can be obtained by dispersing these nanoparticles in a surfactant/solution and extracting the supernatant after centrifugation but the yield of MNPs is low [128,134]. In the top-down approach, bulk materials break down in to powders and then nanoparticles.…”

Recent Advances in Surface Functionalization of Magnetic Nanoparticles

“…It is noteworthy that other compounds such as nitrides γ′-Fe4N, through a consecutive reduction and nitridation strategy, have gained research momentum due to their superior magnetic Magnetization of the magnetic core is highly important, as it further dictates the final behavior of the magnetic nanoplatform when subjected to a magnetic field. It is noteworthy that other compounds such as nitrides γ -Fe 4 N, through a consecutive reduction and nitridation strategy, have gained research momentum due to their superior magnetic properties when compared to typical IONPs (Figure 7) [66]. Such a new magnetic core (M S = 182.7 emu/g for γ -Fe 4 N) could yield novel high-performance magnetic nanoplatforms.…”

Interface-Engineered Mesoporous FeB with Programmed Drug Release for Synergistic Cancer Theranostics

“…Among them, iron-based nanostructures stand out because the exogenous administration of an essential element would avoid the potential adverse effects to human health. To date, tremendous efforts have been devoted to developing Fe-based oxides, , sulfides, , carbides, − nitrides, − and Fe-based MOFs, − where the Fe-based MOF with a mesoporous structure witnesses obvious renown due to its inherent advantage in carrying chemotherapeutic drugs as well as multi-therapeutic modes. Of note, the facile synthesis of mesoporous Fe-based sulfides, carbides, and nitrides to be developed as nanoagents has long been a challenge.…”