Synthesis and Characterization of Magnetic Composite Theragnostics by Nano Spray Drying

Abstract

Composites of magnetite nanoparticles encapsulated with polymers attract interest for many applications, especially as theragnostic agents for magnetic hyperthermia, drug delivery, and magnetic resonance imaging. In this work, magnetite nanoparticles were synthesized by coprecipitation and encapsulated with different polymers (Eudragit S100, Pluronic F68, Maltodextrin, and surfactants) by nano spray drying technique, which can produce powders of nanoparticles from solutions or suspensions. Transmission and scanning electron microscopy images showed that the bare magnetite nanoparticles have 10.5 nm, and after encapsulation, the particles have approximately 1 μm, with size and shape depending on the material’s composition. The values of magnetic saturation by SQUID magnetometry and mass residues by thermogravimetric analysis were used to characterize the magnetic content in the materials, related to their magnetite/polymer ratios. Zero-field-cooling and field-cooling (ZFC/FC) measurements showed how blocking temperatures of the powders of the composites are lower than that of bare magnetite, possibly due to lower magnetic coupling, being an interesting system to study magnetic interactions of nanoparticles. Furthermore, studies of cytotoxic effect, hydrodynamic size, and heating capacity for hyperthermia (according to the application of an alternate magnetic field) show that these composites could be applied as a theragnostic material for a non-invasive administration such as nasal.

Synthesis and characterization of magnetite coated by maltodextrin for application in magnetic hyperthermia

“…73 Perecin et al (2021) highlight the critical nature of the nucleation step in obtaining high SAR values, emphasizing the influence of saturation magnetization, crystallinity, size, concentration, and value of the applied alternating magnetic field on this parameter. 44 However, it is imperative to note that, as previously observed, the nucleation process was compromised with the addition of maltodextrin in the system, particularly in samples S1, S2, and S3. In these instances, the incorporation of maltodextrin led to a deviation from the optimal nucleation conditions.…”

“…20 Coprecipitation synthesis is a chemical method involving a nucleation stage followed by a growth stage and is currently one of the most widely employed methods due to its simplicity compared to other synthesis methods, as well as its high yields and economic advantages. 44,45 However, factors such as crystal growth control, nucleation, and agglomeration processes still need to be studied, as they are not fully understood when working with nanoscale sizes. 1,43,44,46 Additionally, magnetite nanoparticles are not stable when in contact with oxygen and are easily prone to oxidation, reducing or losing their magnetic characteristics.…”

“…44,45 However, factors such as crystal growth control, nucleation, and agglomeration processes still need to be studied, as they are not fully understood when working with nanoscale sizes. 1,43,44,46 Additionally, magnetite nanoparticles are not stable when in contact with oxygen and are easily prone to oxidation, reducing or losing their magnetic characteristics. 41,43 Over time, single-domain superparamagnetic particles may agglomerate to decrease the free surface energy due to magnetic dipole attraction, resulting in low stability and dispersibility.…”

“…10 It has the molecular formula (C 6 H 10 O 5 ) n and consists of three to seventeen units of D-glucose linked mainly by a 1-4 glycosidic bonds. 44,49 Due to its long carbohydrate chains, it is considered a complex carbohydrate, similar to glucose, 50 with relatively low cost, low viscosity at high concentrations, good protection against oxidation, 51 and increased stability. 52 Its structure comprises glucose molecules, which can attract cancer tissues due to the high affinity from glucose to malignant cells.…”

“…52 Its structure comprises glucose molecules, which can attract cancer tissues due to the high affinity from glucose to malignant cells. 42,44 In this context, this study aims at the cost-effective production of superparamagnetic magnetite nanoparticles by proposing a novel coating with maltodextrin. It follows an experimental planning for optimal synthesis based on results from statistical analysis.…”