Magnetic Response of Nano/Microparticles into Elastomeric Electrospun Fibers

Abstract

Combining magnetic nanoparticles (MNPs) with high-voltage processes to produce ultra-thin magnetic nanofibers (MNFs) fosters the development of next-generation technologies. In this study, polycarbonate urethane nanofibers incorporating magnetic particles were produced via the electrospinning technique. Two distinct types of magnetic payload were used: (a) iron oxide nanoparticles (IONPs) with an average size and polydispersity index of 7.2 nm and 3.3%, respectively; (b) nickel particles (NiPs) exhibiting a bimodal size distribution with average sizes of 129 nanometers and 600 nanometers, respectively, and corresponding polydispersity indexes of 27.8% and 3.9%. Due to varying particle sizes, significant differences were observed in their aggregation and distribution within the nanofibers. Further, the magnetic response of the IONP and/or NiP-loaded fiber mats was consistent with their morphology and polydispersity index. In the case of IONPs, the remanence ratio (Mr/Ms) and the coercive field (Hc) were found to be zero, which agrees with their superparamagnetic behavior when the average size is smaller than 20–30 nm. However, the NiPs show Mr/Ms = 22% with a coercive field of 0.2 kOeas expected for particles in a single or pseudo-single domain state interacting with each other via dipolar interaction. We conclude that magnetic properties can be modulated by controlling the average size and polydispersity index of the magnetic particles embedded in fiber mats to design magneto-active systems suitable for different applications (i.e., wound healing and drug delivery).

Generation of Photopolymerized Microparticles Based on PEGDA Hydrogel Using T-Junction Microfluidic Devices: Effect of the Flow Rates

“…On the left are images corresponding to SEM images, and on the right are graphics representing the size distribution of MPs, where N is the number of MPs counted, size media is the mean of diameters, St desv (%) is the standard deviation of the diameter, and PDI is the value of the polydispersity index; in the abscissa is the diameter (µm) and in the ordinate is the frequency (%). With the obtained statistical data, the PDI was calculated with Equation (3) based on the criteria of considering MPs homogeneous when the value of the PDI was lower than 0.05 [ 48 ].…”

“…Therefore, monodispersity defines the degree of uniformity of the MPs , and PDI is represented in Equation (2), where St Desv is the standard deviation of the diameter and the size of the mean is the mean of the diameters. The value of PDI is utilized as the criteria to determine if the system presents a monodisperse pattern; if the value is under 0.05, the particles are considered homogeneous and/or have little size variation with respect to each other [ 25 , 48 ]. Another way to validate the monodisperse patterns of MPs is the coefficient of variation (CV), that is, St Desv divided by the size of the media: .…”

Remote-Controlled Activation of the Release through Drug-Loaded Magnetic Electrospun Fibers

“…When AMFs are applied to the embedded MNPs, several phenomena occur, enabling remote-controlled release. These include magnetic heating [12], mechanical actuation [13], spatial control [14], and the modulation of the release rate [15]. Concerning the capacity for remote magnetic heating, the efficiency with which magnetic nanoparticles (MNPs) respond to alternating magnetic fields (AMFs) is strongly influenced by their size, magnetic anisotropy, and degree of agglomeration.…”

Beyond the Passive Diffusion: Core@Satellite Magneto‐Plasmonic Particles for Rapid and Sensitive Colorimetric Immunosensor Response

“…[11,12] On the other hand, the effectiveness of controlling functionalized materials using magnetic nano/microparticles through the use of an external magnetic field is well known. [13] The widely used magnetic material is iron oxide composite Fe 3 O 4 , which shows superparamagnetism for a NP diameter less than 20 nm. [14] Magnetic NP (MNP) clusters are frequently utilized, offering an enhanced and cooperative magnetic response that results in improved saturation magnetization and reduced coercive field at low temperatures.…”