Reproducibility and Scalability of Magnetic Nanoheater Synthesis

Abstract

The application of magnetic nanoparticles requires large amounts of materials of reproducible quality. This work explores the scaled-up synthesis of multi-core iron oxide nanoparticles through the use of thermal decomposition in organic media and kilograms of reagents. To this end, we check the effect of extending the high temperature step from minutes to hours. To address the intrinsic variability of the colloidal crystallization nucleation process, the experiments were repeated and analyzed statistically. Due to the simultaneity of the nuclei growth and agglomeration steps, the nanostructure of the samples produced was a combination of single- and multi-core nanoparticles. The main characteristics of the materials obtained, as well as the reaction yields, were analyzed and compared. As a general rule, yield, particle size, and reproducibility increase when the time at high temperature is prolonged. The samples obtained were ranked in terms of the reproducibility of different structural, colloidal, and magnetic features. The capability of the obtained materials to act as nanoheaters in magnetic hyperthermia was assessed, showing a strong dependence on the crystallite size (calculated by X-ray diffraction), reflecting the nanoparticle volume with a coherent magnetization reversal.

The delicate balance of phase speciation in bimetallic nickel cobalt nanoparticles

“…On a more general note, we call for a more systematic report of nanoparticles syntheses that are highly sensitive to operating conditions, because robustness is a key issue of nanotechnology developments. [54][55][56] Although these may have been so far flying under the radar, being sometimes considered as "negative results", this will be enlightening to the community as an effort to strengthen our protocols, and this will also be key to successful implementation of automated methods and analysis in NPs synthetic design, e.g. using AI technologies.…”

Iron oxide and iron oxyhydroxide nanoparticles impair SARS-CoV-2 infection of cultured cells

“…DMSA-IONP suspensions are aqueous colloids of an iron oxide magnetite core with a 10 or 16 nm diameter, as determined by Transmission Electron Microscopy (TEM, denominated as DMSA-IONP-10 and DMSA-IONP-16, respectively). The coated NPs were prepared by thermal decomposition of Fe(acac) 3 in the presence of oleic acid (OA) as a surfactant and coated with DMSA by ligand exchange, as described previously [ 31 , 32 ]. The biocompatible coating surrounding the iron plays a crucial role in stabilizing the iron core, slowing down the release of iron, protecting the particles from further aggregation, and sustaining the particles in a colloidal suspension that can be injected intravenously.…”

“…DMSA-IONP suspensions are aqueous colloids of an iron oxide magnetite core with a 10 or 16 nm diameter, as determined by Transmission Electron Microscopy (TEM, denominated as DMSA-IONP-10 and DMSA-IONP-16, respectively). The coated NPs were prepared by thermal decomposition of Fe(acac) 3 in the presence of oleic acid (OA) as a surfactant and coated with DMSA by ligand exchange, as described previously [31,32].…”

Ferrofluids and bio-ferrofluids: looking back and stepping forward

“…The scale-up synthesis of bio-ferrofluids for magnetic hyperthermia was recently considered in a complex investigation concerning the reproducibility and scalability of the thermal decomposition procedure involving kilograms of reagents and cheap commercial precursors. 105 To obtain large quantities of single core and multi-core magnetite nanoparticles the scale-up procedure applied refers to the decomposition of iron( iii ) acetylacetonate 99% in benzyl ether in the presence of oleic acid and 1,2-dodecanediol 90%, with substantial modifications of the lab-scale synthesis, such as the extension of the high temperature step from minutes to hours. The results of large-scale synthesis were evaluated by thorough comparative analyses of the solvodynamic size average values and magnetic heating characteristics under different field conditions measured for toluene-based suspensions of oleic acid stabilized magnetite nanoparticles.…”