Magnetic Drug Targeting System Research Articles

Two-phase bio-nanofluid flow through a bifurcated artery with magnetic field interaction

A modified multiphase flow model is applied for a better understanding of bio-nanofluid (blood containing 4% (w/v) Fe3O4 nanoparticles) flow regimes through a real bifurcated artery. The magnetic field with distinct current intensities (I = 0 – 300 A) was employed to induce the flow features when the wire's source is placed nearby the junction of the asymmetrical branched artery during numerical computation. The finite volume method was used to solve the coupled hemodynamics model. Results show that the pressure, and vorticity profiles increased and fallen gradually with the existence of the magnetic source and further obtained the maximum pressure for the strong current intensity (I = 300 A). The fluctuating vorticity distributions are found along the inner and outer vessel wall as well as the predicted lines created within the simulated domain for the increase of current intensity. The velocity outlines variates steadily, and the local peak velocities are obtained with the increase of the magnetic force. With the increment of the current intensity upto I = 300 A, the flow rate rises progressively for the asymmetric branched vessel, and the opposite scenario is found for the root vessel. The temperature profiles decrease steadily with the increment of the applied current intensity. With the manifestation of the magnetic source, the irregular flow behaviours are found within the asymmetrical bifurcated artery. This modeling investigation could be beneficial for the emergent therapy plan of ample vascular diseases as the magnetic drug targeting system.

Dynamics of Williamson Ferro-nanofluid due to bioconvection in the portfolio of magnetic dipole and activation energy over a stretching sheet

The significance of the present work is that it is very useful in different fields of bio-engineering and engineering including magnetic drug targeting systems, magnetic hyperthymia, directing of magnetic drugs and etc. This paper explored the mechanical features of the magnetic dipole, activation energy and chemical reaction over the MHD flow of two-dimensional non-Newtonian Williamson Ferro-nanofluid under the stretched surface. The main aim of using the magnetic dipole effect in this problem is to control the momentum and thermal boundary layer thickness with the combining impact of nanofluid. As a result, the current approach is extremely valuable for controlling the thickness of thermal and momentum boundary layers. The thermal radiation and heat source/sink impacts are included in the heat equation for the calculation of heat transmission phenomena. The role of the gyrotactic microorganisms is discussed in the present analysis. The influence of Brownian motion and thermophoresis are also examined. The present mechanical system is formulated in the form of the higher-order PDEs and these nonlinear PDEs are relocated into the nonlinear higher-order ODEs by using the suitable similarity transformations. In the methodology section, for the solution of these highly nonlinear ODEs, the homotopic analysis scheme is employed. The effects of distinct flow parameters on the velocity, temperature, concentration and motile gyrotactic microorganism of the Williamson nanoliquid are scrutinized and discoursed in a graphical form. The following are some key outcomes from this analysis, it is predicted that the speed of the nanoliquid particles is lesser for nanoparticle volume fraction. Also, it is examined that the activation energy boosted the nanofluid concentration. Computation for streamline is performed in the present study.

Numerical study on targeted delivery of magnetic drug particles in realistic human lung

Inhalation of medical drug particles through human airway is widely utilized for the remedy of lung diseases. Due to the complexities of airway morphology, flow turbulence and particle deposition, the drug delivery efficiency to the morbid region of lung is always unsatisfactory. In this research, a 3D anatomically accurate human airway model from oral cavity to lung is reconstructed, and the large eddy simulation-discrete phase model (LES-DPM) is adopted to simulate the airway flow and drug particles transport. To improve the particle delivery to the targeted region of the left lung, a magnetic drug targeting (MDT) system is established. It is found that the LES-DPM in conjunction with MDT system is an effective tool to study airway flow patterns and magnetic particle deposition features. Moreover, the magnetic source layout, magnetic particle size and magnetic field intensity all have significant impacts on the particle deposition efficiency in the left lung. Optimal combination factors for drug particle delivery results are successfully achieved. The total deposition efficiency of magnetic particles in the left lung can be increased to more than 5 times. This work not only could provide a better understanding of air-particle dynamics, but also could contribute toward improved strategies for more efficient drug delivery in the realistic human lungs.

Exploring magnetic dipole contribution on ferromagnetic nanofluid flow over a stretching sheet: An application of Stefan blowing

The study is achieved to explore the novel of a two-dimensional ferromagnetic fluid flow over a flat elastic sheet with the magnetic dipole effect. The flow design was chosen because it is often used in engineering and bioengineering applications including magnetic drug targeting systems. The Buongiorno model has been used to incorporate Brownian movement and thermophoresis effects. Further, Stefan blowing effect and convective boundary constraint is taken in to the account. The governing expressions for assumed flow are reduced to ordinary differential equations by opting suitable similarity variables. The reduced equations are solved using Runge–Kutta–Fehlberg 45 method by adopting Shooting technique. The attained numerical outcomes are then illustrated graphically . Result reveals that, upsurge in values of thermophoresis and Brownian motion parameters improves the thermal gradient and the fluid shows high heat transfer in existence of Stefan blowing condition. Convective boundary condition has tendency to improve the heat transfer feature of liquid in presence of Stefan blowing condition. Further, the justification of current outcomes is accomplished by developing comparison with available published work.

Optimal Design and Implementation of a Novel Two-Dimensional Electromagnetic Navigation System That Allows Focused Heating of Magnetic Nanoparticles

A magnetic drug-targeting system featuring real-time imaging, guidance, and local heating is required for more precise drug targeting and minimization of side effects. In this article, we present a novel electromagnetic navigation and heating system that not only guides and navigates magnetic nanoparticles (MNPs) with real-time imaging feedback, but also uses focused MNP heating to release drugs while monitoring the temperature. The magnetic field amplitude and magnetic gradient play key roles in our integrated system; we enhanced the gradient and field within a field of view of 30 × 30 mm. Performance was examined via simulation employing COMSOL Multiphysics software and verified experimentally. After optimization, the maximum gradients attained on the x and y axes are 4.15 and 2.23 T/m/μ0, respectively, for the electromagnetic actuator mode, and 8.48 T/m/μ0 for the magnetic particle imaging mode. The magnetic field amplitude for heating was 19.70 mT at 100 kHz. We then built a two-dimensional MNPs navigation/heating system to demonstrate the in vitro feasibility of our scheme; this afforded a 1-Hz navigation update rate during MNPs guidance in a Y-shaped channel and locally heated MNPs with temperature monitoring.

Understanding the dynamics of superparamagnetic particles under the influence of high field gradient arrays

The aim of this study was to characterize the behaviour of superparamagnetic particles in magnetic drug targeting (MDT) schemes. A 3-dimensional mathematical model was developed, based on the analytical derivation of the trajectory of a magnetized particle suspended inside a fluid channel carrying laminar flow and in the vicinity of an external source of magnetic force. Semi-analytical expressions to quantify the proportion of captured particles, and their relative accumulation (concentration) as a function of distance along the wall of the channel were also derived. These were expressed in terms of a non-dimensional ratio of the relevant physical and physiological parameters corresponding to a given MDT protocol.The ability of the analytical model to assess magnetic targeting schemes was tested against numerical simulations of particle trajectories. The semi-analytical expressions were found to provide good first-order approximations for the performance of MDT systems in which the magnetic force is relatively constant over a large spatial range.The numerical model was then used to test the suitability of a range of different designs of permanent magnet assemblies for MDT. The results indicated that magnetic arrays that emit a strong magnetic force that varies rapidly over a confined spatial range are the most suitable for concentrating magnetic particles in a localized region. By comparison, commonly used magnet geometries such as button magnets and linear Halbach arrays result in distributions of accumulated particles that are less efficient for delivery.The trajectories predicted by the numerical model were verified experimentally by acoustically focusing magnetic microbeads flowing in a glass capillary channel, and optically tracking their path past a high field gradient Halbach array.

Visualization and Motion of Curcumin Loaded Iron Oxide Nanoparticles During Magnetic Drug Targeting

Magnetic drug targeting (MDT) involves the localization of drug loaded iron oxide nanoparticles (IONPs) around the malignant tissue using external magnetic field for therapeutic purposes. The present in vitro study reports the visualization and motion of curcumin loaded IONPs (CU-IONPs) around the target site inside a microcapillary (500 × 500 μm2 square cross section), in the presence of an externally applied magnetic field. Application of magnetic field leads to transportation and aggregation of CU-IONPs toward the target site inside the capillary adjacent to the magnet. The localization/aggregation of CU-IONPs at the target site shows strong dependence on the strength of the applied magnetic field and flow rate of ferrofluid through the capillary. Such an in vitro study offers a viable for optimization and design of MDT systems for in vivo applications.

Modelling the effect of SPION size in a stent assisted magnetic drug targeting system with interparticle interactions.

Cancer is a leading cause of death worldwide and it is caused by the interaction of genomic, environmental, and lifestyle factors. Although chemotherapy is one way of treating cancers, it also damages healthy cells and may cause severe side effects. Therefore, it is beneficial in drug delivery in the human body to increase the proportion of the drugs at the target site while limiting its exposure at the rest of body through Magnetic Drug Targeting (MDT). Superparamagnetic iron oxide nanoparticles (SPIONs) are derived from polyol methods and coated with oleic acid and can be used as magnetic drug carrier particles (MDCPs) in an MDT system. Here, we develop a mathematical model for studying the interactions between the MDCPs enriched with three different diameters of SPIONs (6.6, 11.6, and 17.8 nm) in the MDT system with an implanted magnetizable stent using different magnetic field strengths and blood velocities. Our computational analysis allows for the optimal design of the SPIONs enriched MDCPs to be used in clinical applications.

Ferrofluid pipe flow under the influence of the magnetic field of a cylindrical coil

Ferrofluid pipe flow under the effect of a co-linear, finite length cylindrical coil is examined numerically. The specific flow configuration is chosen as it is encountered in engineering and bioengineering applications such as magnetic drug targeting systems. The objective of the paper is twofold: first, to investigate the accuracy of an analytical solution for the magnetization equation and assess its validity when used for non-uniform magnetic fields. It is found that it can be very helpful as a means of estimating the magnetization, especially for strong magnetic fields with low gradients; second, to examine the effects of the magnetic field on the flow and study the relevant importance of the magnetic terms of the momentum equation. The parameters that we examine are the strength of the magnetic field and of its gradients, the volumetric concentration of the magnetic particles, and the dimensions (length and diameter) of the coil. It is revealed that the axial pressure drop depends linearly on the volumetric concentration and that the magnetoviscosity effect is negligible in cases of non-uniform magnetic fields.

Magnetic Drug Targeting as New Therapeutic Option for the Treatment of Biomaterial Infections

Implant-associated infections are a challenging problem in surgery. Bacteria in biofilms are difficult to treat as they are less susceptible to antibiotics or antiseptics which require high drug concentrations at the site of infection. We present a novel strategy to concentrate high antibiotic doses systemically at the target site using newly developed antibiotic-functionalized nanoparticles directed by a magnetic drug-targeting system. The important and effective antibiotic gentamicin served as antimicrobial substance and was ionically or covalently attached to magnetic nanoparticles. Subsequently, the particles were characterized thoroughly. Anti-infective properties with regard to Staphylococcus aureus and the degree of cytotoxicity concerning human umbilical vein endothelial cells were determined. The enrichment of the magnetic nanoparticles at the surface of model tubes in circulatory experiments was investigated. We describe a promising technique for the loading of magnetic nanoparticles to treat systemic infections. Gentamicin-coated magnetic nanoparticles reduced bacterial growth even beyond pathologically relevant concentrations within 24 h. Excellent concentration independent biocompatibility was found for the nanoparticles themselves and we demonstrate that the magnetic nanoparticles can be navigated and concentrated on surfaces of model implants using a permanent magnetic field.

A novel pH-sensitive magnetic alginate–chitosan beads for albendazole delivery

Background: Drug delivery system using polymer-coated magnetic carriers is considered as an effective strategy for passive targeting, which can not only increase drug utilization but also reduce the adverse reaction. With the carriers, sensitivity to physical stimuli (e.g., magnetic field, pH) has been developed and drugs were conjugated to form incorporating magnetic particles, so that drugs could be located to desire position. Method: Novel magnetic alginate (Alg)–chitosan (CS) beads loaded with albendazole (ABZ) were prepared and evaluated for pH sensitivity and drug release characteristics. The effects of six different factors (Alg concentration, the weight ratio of drug to polymer, the weight ratio of magnetite nanoparticles to polymer, CaCl2 concentration, CS concentration, the volume ratio of Alg to CS) were studied on the swelling ability of the magnetic beads. The magnetic beads were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, and vibrating sample magnetometry. In addition, the delivery behavior of ABZ from the magnetic beads was studied. Result: The magnetic Alg–CS beads had showed unique pH-dependent swelling behaviors and a continuous release of ABZ. From the magnetometer measurements data, the beads also had superparamagnetic property as well as fast magnetic response. Conclusion: The pH-sensitive magnetic beads may be used as a magnetic drug targeting system for ABZ in the gastrointestinal tract.

PH-sensitive magnetic alginate-chitosan beads for albendazole delivery

Novel magnetic alginate-chitosan beads were prepared for the controlled delivery of albendazole. The magnetic beads were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and vibrating sample magnetometry (VSM). The swelling behavior and in vitro release of albendazole from the beads has been investigated. The magnetic hydrogel beads had showed unique pH-dependent swelling behaviors and a continuous release of the entrapped albendazole occurred. From the magnetometer measurements data, the magnetic alginate-chitosan beads also had superparamagnetic property as well as fast magnetic response. The magnetic beads may be used as a magnetic drug targeting system for albendazole in the gastrointestinal tract.

Particle size, magnetic field, and blood velocity effects on particle retention in magnetic drug targeting

A physics-based model of a general magnetic drug targeting (MDT) system was developed with the goal of realizing the practical limitations of MDT when electromagnets are the source of the magnetic field. The simulation tracks magnetic particles subject to gravity, drag force, magnetic force, and hydrodynamic lift in specified flow fields and external magnetic field distributions. A model problem was analyzed to determine the effect of drug particle size, blood flow velocity, and magnetic field gradient strength on efficiency in holding particles stationary in a laminar Poiseuille flow modeling blood flow in a medium-sized artery. It was found that particle retention rate increased with increasing particle diameter and magnetic field gradient strength and decreased with increasing bulk flow velocity. The results suggest that MDT systems with electromagnets are unsuitable for use in small arteries because it is difficult to control particles smaller than about 20 microm in diameter.

Inclusion of magnetic dipole–dipole and hydrodynamic interactions in implant-assisted magnetic drug targeting

Mathematical modelling of the implant-assisted magnetic drug targeting system of Avilés, Ebner and Ritter is performed. In order to model the agglomeration of particles known to occur in this system, the magnetic dipole–dipole and hydrodynamic interactions are included. Such interactions were calculated previously by Mikkelsen et al. under low magnetic fields (~0.05 T) in microfluidic systems. Here, a higher magnetic field (0.7 T) is considered and the effect of interactions on two nanoparticles with a seed implant is calculated. The calculations were performed with the open-source software OpenFOAM. Different initial positions are considered and the system performance is assessed in terms of capture cross section. Inclusion of both interactions was seen to alter the capture cross section of the system by up to 7% in absolute terms.

Analysis of magnetic drug carrier particle capture by a magnetizable intravascular stent: 1. Parametric study with single wire correlation

The feasibility of using a magnetizable intravascular stent (MIS) as part of a magnetic drug targeting (MDT) system, which consists of magnetic drug carrier particles (MDCPs), an external magnetic field source, and the MIS, is introduced and theoretically analyzed. This new approach exploits the use of high gradient magnetic separation (HGMS) principles through the MIS, which has been placed in a blood vessel adjacent to the target site, to vastly improve the targeting of the MDCPs at this site. The performance of the MDT system was based on the ability of one of the wires in the MIS to capture the MDCPs, with the capture cross-section evaluated from a single wire HGMS correlation in the literature. A parametric study showed that the dimensionless capture cross section (with respect to the wire radius) increases with lower blood velocities (0.02–0.9m/s), higher applied magnetic field strengths (0.2–2.0T), larger MDCPs (0.2–10μm radius) containing more (10–100%) and stronger ferromagnetic material (iron>magnetite), and smaller wires (20–150μm in radius) comprised of stronger ferromagnetic material (iron>430 SS>nickel>304 SS). Reasonable capture cross-sections, ranging between 2 and 3, but as high as 12, times the radius of the wire, were easily attained with just a single wire and under extreme flow conditions of 0.9m/s that are typical of large arteries. Overall, these results show considerable promise for an HGMS-assisted MDT system with many potential applications for MIS devices.

Application of high gradient magnetic separation principles to magnetic drug targeting

A hypothetical magnetic drug targeting system, utilizing high gradient magnetic separation (HGMS) principles, was studied theoretically using FEMLAB simulations. This new approach uses a ferromagnetic wire placed at a bifurcation point inside a blood vessel and an externally applied magnetic field, to magnetically guide magnetic drug carrier particles (MDCP) through the circulatory system and then to magnetically retain them at a target site. Wire collection (CE) and diversion (DE) efficiencies were defined and used to evaluate the system performance. CE and DE both increase as the strength of the applied magnetic field (0.3–2.0T), the amount of ferromagnetic material (iron) in the MDCP (20–100%) and the size of the MDCP (1–10μm radius) increase, and as the average inlet velocity (0.1–0.8ms−1), the size of the wire (50–250μm radius) and the ratio (4–10) of the parent vessel radius (0.25–1.25mm radius) to wire radius decrease. The effect of the applied magnetic field direction (0° and 90°) on CE and DE was minimal. Under these plausible conditions, CEs as high as 70% were obtained, with DEs reaching only 30%; however, when the MDCPs were allowed to agglomerate (4–10μm radius), CEs and DEs of 100% were indeed achieved. These results reveal that this new magnetic drug targeting approach for magnetically collecting MDCPs at a target site, even in arteries with very high velocities, is feasible and very promising; this new approach for magnetically guiding MDCPs through the circulatory system is also feasible but more limited. Overall, this study shows that magnetic drug targeting, based on HGMS principles, has considerable promise as an effective drug targeting tool with many potential applications.