Browsing by Author "Wu, Xian"
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Item Kinetic and Parametric Analysis of the Separation of Ultra-Small, Aqueous Superparamagnetic Iron Oxide Nanoparticle Suspensions under Quadrupole Magnetic Fields(2023) Ciannella, Stefano (TTU); Wu, Xian; González-Fernández, Cristina (TTU); Rezaei, Bahareh; Strayer, Jacob; Choe, Hyeon; Wu, Kai; Chalmers, Jeffrey; Gomez-Pastora, Jenifer (TTU)Superparamagnetic iron oxide nanoparticles (SPIONs) have gathered tremendous scientific interest, especially in the biomedical field, for multiple applications, including bioseparation, drug delivery, etc. Nevertheless, their manipulation and separation with magnetic fields are challenging due to their small size. We recently reported the coupling of cooperative magnetophoresis and sedimentation using quadrupole magnets as a promising strategy to successfully promote SPION recovery from media. However, previous studies involved SPIONs dispersed in organic solvents (non-biocompatible) at high concentrations, which is detrimental to the process economy. In this work, we investigate, for the first time, the magnetic separation of 20 nm and 30 nm SPIONs dispersed in an aqueous medium at relatively low concentrations (as low as 0.5 g·L−1) using our custom, permanent magnet-based quadrupole magnetic sorter (QMS). By monitoring the SPION concentrations along the vessel within the QMS, we estimated the influence of several variables in the separation and analyzed the kinetics of the process. The results obtained can be used to shed light on the dynamics and interplay of variables that govern the fast separation of SPIONs using inexpensive permanent magnets.Item Measuring magnetic force field distributions in microfluidic devices: Experimental and numerical approaches(2023) Strayer, Jacob; Choe, Hyeon; Wu, Xian; Weigand, Mitchell; Gómez-Pastora, Jenifer (TTU); Zborowski, Maciej; Chalmers, Jeffrey J.Precisely and accurately determining the magnetic force and its spatial distribution in microfluidic devices is challenging. Typically, magnetic microfluidic devices are designed in a way to both maximize the force within the separation region and to minimize the necessity for knowing such details—such as designing magnetic geometries that create regions of nearly constant magnetic force or that dictate the behavior of the magnetic force to be highly predictable in a specified region. In this work, we present a method to determine the spatial distribution of the magnetic force field in a magnetic microfluidic device by particle tracking magnetophoresis. Polystyrene microparticles were suspended in a paramagnetic fluid, gadolinium, and this suspension was exposed to various magnetic field geometries. Polystyrene particle motion was tracked using a microscope and images processed using Fiji (ImageJ). From a sample with a large spatial distribution of particle tracks, the magnetic force field distribution was calculated. The force field distribution was fitted to nonlinear spatial distribution models. These experimental models are compared to and supported by 3D simulations of the magnetic force field in COMSOL.Item SPIONs Magnetophoresis and Separation via Permanent Magnets: Biomedical and Environmental Applications(2023) Wu, Xian; Ciannella, Stefano (TTU); Choe, Hyeon; Strayer, Jacob; Wu, Kai; Chalmers, Jeffrey; Gomez-Pastora, Jenifer (TTU)Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as cutting-edge materials, garnering increasing attention in recent years within the fields of chemical and biomedical engineering. This increasing interest is primarily attributed to the distinctive chemical and physical properties of SPIONs. Progress in nanotechnology and particle synthesis methodologies has facilitated the fabrication of SPIONs with precise control over parameters such as composition, size, shape, stability, and magnetic response. Notably, these functionalized materials exhibit a remarkable surface-area-to-volume ratio, biocompatibility, and, most importantly, they can be effectively manipulated using external magnetic fields. Due to these exceptional properties, SPIONs have found widespread utility in the medical field for targeted drug delivery and cell separation, as well as in the chemical engineering field, particularly in wastewater treatment. Magnetic separation techniques driven by magnetophoresis have proven to be highly efficient, encompassing both high-gradient magnetic separation (HGMS) and low-gradient magnetic separation (LGMS). This review aims to provide an in-depth exploration of magnetic field gradient separation techniques, alongside a comprehensive discussion of the applications of SPIONs in the context of drug delivery, cell separation, and environmental remediation.