Magnetic Drug Targeting Research Articles

Microgravity influenced unsteady dispersion during magnetic drug targeting in an inclined tumor-stenosed microvessel with slip effects

Introduction:Recent cancer research into microgravity or altered gravity environments has gained attention for its potential to disrupt cancer cell growth and proliferation while reducing the risk of chemoresistance—a major challenge in conventional chemotherapy. Aim of the study:Motivated by the emerging applications of microgravity in cancer research, the current study aimed to mathematically investigate the potential of the microgravity-enhanced environment in combination with magnetic drug targeting (MDT) to optimize drug delivery and dispersion. Methodology:The particle velocity, including microgravity’s influence in the presence of an external applied magnetic field alongside fluid pressure, was computed analytically while the solute dispersion model was numerically evaluated using the Crank–Nicolson method. Results:Findings show that microgravity lowers particle concentration in the tumor, however, improved drug-loaded magnetic nanoparticle properties, and magnetic field strength reveal a positive impact on nanoparticle accumulation. Also, altered stenosis height, inclination angle, slip velocity, and other control parameters such as Peclet number, magnetic-tumor distance, drug source term, elimination, and local skin friction revealed significant differences in particle dispersion behavior before, within, and after the stenosis region. Conclusion:Our results suggest potential future therapeutic applications of altered gravity in combination with MDT phenomena to improve drug delivery for noninvasive therapeutic strategies.

Enhancing capture efficiency of drug-carrier particles in the carotid sinus by utilizing a combination of magnetic fields: A numerical approach

Magnetic drug targeting is a relatively new method to treat vascular occlusion in different body parts. However, the effectiveness of this method can be affected due to the severity and location of the occlusion. This can lead to the injection of high dosages of drugs, which can cause serious side effects due to the deposition of drugs in unwanted parts. To mitigate these effects, this study investigates the potential of a guiding magnetic field in enhancing drug absorption for vascular occlusion treatment. The method relies on guiding magnetic nanoparticles (NPs) loaded with drugs toward the occlusion site using two external magnetic fields. Blood flow was modeled as non-Newtonian, considering shear-rate-dependent viscosity and unsteady at the inlet. To test this idea, a computational fluid dynamic (CFD) coupled with a discrete phase model (DPM) approach has been employed to simulate drug delivery in three-vessel structures with varying degrees of occlusion (45 %, 60 %, and 90 %). To avoid the escape of drug carriers, a secondary magnetic field was applied at the bifurcation point to direct the NPs to the site of blockage where the primary magnetic field acts. Then, the states with or without a guiding source at the bifurcation site are compared based on the capture efficiency of each structure. The simulation demonstrated a significant increase in NP capture at the target site, ranging from 2 % to 15 %, depending on the NP size. However, the severity of occlusion substantially impacted the secondary magnetic field's effectiveness. In the 90 % occlusion scenario, the method's efficiency decreased significantly from 26 % to 16 % for NP sizes exceeding 1.5μm. This study highlights the potential of guiding magnetic fields in improving drug delivery to target sites in vascular occlusion.

Molecular dynamics modelling of interacting magnetic nanoparticles for investigating equilibrium and dynamic ensemble properties

Magnetic nanoparticles have the potential to be used in various biomedical applications, including magnetic drug targeting and hyperthermia for cancer treatment. In both cases, precise prediction of the local particle concentration is required to plan a successful therapy, which is a challenging task due to several complex flow phenomena. Computational macroscopic and microscopic models have been developed to support this process, but they have limitations in terms of interactions implementation, micromagnetic dynamics or computational costs. This study aims to develop a model that can represent micromagnetic dynamics and being employed to study equilibrium properties of particle ensembles in viscous media. Therefore, a kinetic Monte Carlo method in combination with Langevin equations is used. So, magnetization dynamics and mechanical motion can be simulated in combination very efficiently. The new model is validated with another model based on the stochastic Landau-Lifshitz-Gilbert equation. Various interaction potentials like Van der Waals, steric and electrostatic interactions are included to study their specific influence on structural properties. Also, methods to control the errors while integrating the equations of motion and using the Ewald method for calculating interaction quantities are implemented. As a validation we studied equilibrium and time dependent properties of non-interacting particle ensembles as well as errors made by the Ewald-method used for interaction quantities calculation. In all studies we found very good agreement of the simulation results with the theoretical predictions. The developed models can now be used for investigating equilibrium and dynamic properties of ferrofluids, or more general for biomedical research for magnetic drug targeting, hyperthermia, or imaging techniques. Furthermore, the new hybrid model can be also used for simulations in the range of milliseconds with reasonable computational effort.

Electrical conductivity of Ni ferrite nanofluids: An experimental study on the effects of temperature, volume fraction, and base fluid

This study investigates the electrical conductivity of NiFe2O4 nanofluids in water and ethylene glycol (EG) as base fluids, aiming to understand how varying volume fractions (φ= 0 %, 0.1 %, 0.25 %, 0.45 %, 0.7 %, and 1 %) and temperatures (20–70°C) influence electrical conductivity. NiFe2O4 nanoparticles were synthesized using the chemical co-precipitation method and characterized through X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive Spectroscopy (EDS). The results revealed that at 70°C, the electrical conductivity of NiFe2O4-water nanofluid increased by 1100 % within the volume fraction range of 0–1 %. For NiFe2O4-EG nanofluid, the increase in electrical conductivity was even more significant, reaching 1235 % within the same volume fraction range. Similarly, at a 1 % volume fraction within the temperature range of 20–70°C, the electrical conductivity of NiFe2O4-water nanofluid increased by 136 %, while for NiFe2O4-EG nanofluid, it was 370 %. These findings indicate that both temperature and volume fraction significantly enhance the electrical conductivity of the nanofluids, with a more pronounced effect observed in the NiFe2O4-EG nanofluid compared to the NiFe2O4-water nanofluid. The study validated Shen et al.'s model for electrical conductivity in nanofluids, contrasting with Maxwell's model. The novelty of this work lies in the comprehensive analysis of the electrical conductivity behavior of these nanofluids, which has not been extensively reported in the literature. These findings have potential applications in heat transfer enhancement and magnetic-targeted drug delivery.

Review on Study of Nanoparticles in Brain Targeting for Treatment Of Alzheimer’s

Alzheimer’s disease (AD) is an irreversible neurodegenerative disorder, in which there is a progressive deterioration of intellectual and social functions, memory loss, personality changes and inability for self-care, and has become the fourth leading cause of death in developed countries. Pathogenesis of AD, there is a progressive deposition of β-amyloid (Aβ)- peptide in the hippocampal and cerebral cortical regions. This deposition is associated with the presence of neurofibrillary tangles (NFTs) and senile plaques. The senile plaques deposited between the neurons consist mainly protein β amyloid. Neurofibrillary tangles deposited inside the neurons fabricated from Tau protein. Diagnosing Alzheimer's requires careful medical evaluation thorough medical history, mental status testing, physical and neurological examination tests (such as blood tests and brain imaging), two classes of medications approved to treat AD. Cholinesterase inhibitors: Donepezil, Rivastigmine, Galantamine, NMDA receptor antagonists: Memantine. The major goal in designing nanoparticles as a delivery system are to control particle size, surface property and release of pharmacologically active agents in order to achieve the site-specific action of the drug at the therapeutic optimum rate and dose regimen of the agent to the CNS, but also the ability of the agent to access the relevant target site within the CNS. Many strategies have been developed to deliver the drug into brain by crossing the BBB: chemical delivery systems, magnetic drug targeting or drug carrier systems such as antibodies, liposomes or nanoparticles. Among those, nanoparticles have got a great concentration as the potential targeted drug delivery systems in the brain recently. Keywords: Alzheimer’s disease, β-amyloid, cholinesterase inhibitors, Curcumin nanoparticles.

Potential magnetic drug targeting with magnetite nanoparticles in cancer treatment by enhancer-modifier natural herb and loaded drug

In the present study, we prepared magnetite nanoparticles (MNPs) loaded with natural Moringa oleifera (M. olf) herb and Epilim (Ep) drug to evaluate the anti-cancerous activity against brain cancer cells. All the samples were prepared via co-precipitation approach modified with different concentrations of M. olf and Ep drug at room temperature. The MNPs loaded with drug and natural herb were studied in terms of crystal structure, morphology, colloidal stability, size distribution, and magnetic properties. Field emission scanning electron microscopy (FESEM) images exhibited the morphologies of samples with spherical shape as well as the particles size of 9 nm for MNPs and up to 23 nm for its composites. The results of vibrating sample magnetometer (VSM) indicated the magnetization saturation (Ms) of 42.510 emu/g for MNPs. This value reduced to 16–35 emu/g upon loading MNPs with different concentrations of M. olf and Ep. Fourier transform infrared spectroscopy (FTIR) indicated the chemical interaction between the Ep, M.olf and MNPs. Brunauer-Emmett-Teller (BET) analysis confirmed the largest surface area for MNPs (422.61 m2/g) which gradually reduced on addition of M. olf and Ep indicating the successful loading. The zeta potential measurements indicated that the MNPs and MNPs loaded with M. olf and Ep are negatively charged and can be dispersed in the suspension. Furthermore, U87 human glioblastoma cell line was used for the in vitro cellular studies to determine the efficacy of synthesized MNPs against cancer cells. The results confirmed the anti-proliferative activity of the MNPs loaded with M. olf and Ep.

A numerical study on MHD micropolar nanofluid flow over a Darcian porous stretching surface: impacts of thermophoretic and Brownian diffusions

This article provides a quantitative analysis of the flow of MHD micropolar fluid through a Darcian permeable medium bounded by a stretched surface. The RK45 method, along with the shooting approach, is employed to perform the analysis. The impacts of Joule heating, thermophoretic, and Brownian diffusions over the fluid flow are particularly, focused in this research work. The study's findings can be applied in nanofluid technology for optimizing heat transfer, porous media engineering for designing efficient systems, and magnetohydrodynamics for applications like magnetic drug targeting and liquid metal cooling in nuclear reactors. The nonlinear partial differential equations (PDEs) that govern the flow are altered into nonlinear ordinary differential equations (ODEs) by using appropriate variable similarity transformations. Displayed the graphical effects of various physical factors over the velocity, angular velocity, concentration, and temperature profiles. Velocity profiles are enhancing as the micropolar fluid and porous factor rises whereas the opposite trend exists for the boosting estimations of the magnetic parameter. Temperature distribution is escalating for the rising estimations of the magnetic, Eckert, Brownian, and thermophoresis parameters but there is an opposite scenario deploys as the Prandtl number upsurges. As Schmidt and Brownian motion parameters increase, the micropolar nanoparticle concentration decelerates and elevates when the thermophoresis parameter is boosted. The micro-rotation profiles are enhanced as the values of the micropolar fluid parameter rise. The drag force was enhanced as the magnetic and micropolar fluid parameters upsurged but diminished when the porous parameter was elevated. The rate of heat flow diminishes with higher estimates of the micropolar fluid parameter but improves when the magnetic and Prandtl number parameters increase. The rate of mass flux escalates for the enhanced values of thermophoresis, Brownian, Schmidt, and chemical reaction parameters. Considerable numerical outcomes have been produced and cross-referenced with the latest study, which unveiled remarkable concurrence.

Enhancing magnetic drug targeting efficiency through computational analysis: Investigating Particle-RBC interaction and non-newtonian blood behavior

Cancer stands as a foremost global mortality determinant, characterized by a persistent deficit in therapeutic modalities capable of reliably and efficiently conveying anti-cancer pharmaceutical agents to profound tissue loci. Within this context, magnetic drug targeting (MDT) has emerged as an innovative approach to cancer management, offering the promise of minimal adverse effects. Accordingly, the current investigation endeavors to evaluate the capture efficacy (CE) of drug-loaded nanoparticles under the influence of an external magnetic field. To this end, a cylindrical neodymium magnet (NdFeB) is employed as the magnetic source. The finite element method (FEM) was utilized to solve the governing equations. The effect of several parameters, including particle diameter, drag force, blood properties, magnetic field intensity, blood’s non-Newtonian behavior, and particle-RBC interaction on the CE of nanoparticles has been investigated. Simultaneous effect of interaction forces and non-Newtonian behavior of blood on the capturing nanoparticles at the tumor site is considered as the novelty of the present work. Taking into account these two parameters will provide more realistic results. Finding showed that the magnetic field intensity and particles’ diameter positively affect the nanoparticles’ CE. For example, by increasing particle diameter from 250 nm to 1500 nm, the CE is increased from 22 % to 53 %, respectively. In addition, it was revealed that consideration of the particle-red blood cell (RBC) interaction, on average, causes a decrease in the CE of nanoparticles by up to 20 %. Regarding the non-Newtonian behavior of blood, it was found that considering blood as non-Newtonian fluid would decrease, on average, 25 % of CE of nanoparticles compared to Newtonian fluid. Results revealed that simultaneous considering the non-Newtonian behavior of blood and interaction forces significantly affect the CE of nanoparticles.

Abstract B026: Rotational magnetic drug targeting for leptomeningeal metastases

Abstract Background: Magnetic nanoparticles (MNPs) have potential for enhancing the delivery of therapeutic molecules to cancer cells and micronodules, including non-obstructing metastases within cerebrospinal fluid (CSF) pathways. Rotational magnetic drug targeting (rMDT) takes advantage of the surface-walking capability of clusters of MNPs, which can be activated remotely. Here, we present data related to 1) the creation, characterization, and in vitro testing of a variety of MNPs utilized with bound or unbound chemotherapeutic agents, and 2) the design and construction of four different magnetomotive systems used to propel MNPs at clinically-relevant distances. The goal was to create an in vitro model mimicking conditions found in patients with leptomeningeal metastases. Methods: Gold-iron alloy nanoparticles were combined with biotinylated etoposide via the streptavidin-biotin interaction. Unbound MNPs were tested with etoposide and doxorubicin. MNPs were characterized by techniques including electron microscopy, Zeta potential analysis, and dynamic light scattering. 3D-printed and acrylic trays were used as conduits for measuring translational motion over distances up to 30 cm through saline, culture media, and artifical CSF. MNP velocities were determined by videography. For propelling the MNPs, one electromagnetic system used a Helmholtz pair of coils on each side of an underlying perpendicular coil. The second electromagnetic system utilized 2 angled coils. Two rotating permanent magnet systems used neodymium-boron-iron magnets of different sizes and rotational speeds. Cultured cells included fibroblasts, lung cancer, glioblastoma, and medulloblastoma cell lines. Light microscopy and cytotoxicty assays (by MTT and trypan blue exclusion) were used to assess preservation of tumoricidal activity. Results: In unbound MNP studies, both etoposide and doxorubin could be dispersed over physiologic distances through saline and artificial CSF at velocities exceeding 1 cm/sec - much faster than by diffusion alone. Drugs conveyed in this manner could be transported at 37°C across cell surfaces and retain tumoricidal effect on cultured cells. With rotating magnets, MNPs could be moved against a saline flow rate of 1 cm/sec. In bound MNP studies, true rMDT was possible - all four magnetomotive systems could be shut off, depositing the MNP-drug conjugate at the desired location. Rotating permanent magnets were found to be advantageous for unilateral device design; electromagnetic devices, however, are more likely to be compatible with concurrent magnetic particle imaging (currently under development). Conclusions: These in vitro findings indicate that rMDT within CSF pathways is feasible and should advance to animal studies. Bound MNPs may prove to be more useful for intrathecal use (administered via lumbar puncture or Ommaya reservoir), considering dilutional effects and CSF flow. An improved ability to direct therapeutic agents within CSF would represent a major step forward in the treatment of patients with leptomeningeal metastases. Citation Format: Herbert Engelhard, Alexander Willis, Tolou Shokuhfar, Lamar Mair. Rotational magnetic drug targeting for leptomeningeal metastases [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr B026.

Iron oxide (Fe3O4) and ciprofloxacin loaded magnetic nanoparticles for magnetic drug targeting

Iron oxide (Fe3O4) pristine and ciprofloxacin loaded nanoparticles are synthesized successfully using co-precipitation method. X-ray diffraction analysis confirms the pure phase formation of the synthesized Fe3O4 particles. The grain size of the Fe3O4 calculated from the SEM images comes out to be 50 nm. UV-VIS spectrophotometric analysis indicates the accuracy of the results in which an absorption maximum of blank and ciprofloxacin containing iron oxide (Fe3O4) particle was observed at 260 and 265 nm respectively. The spectrum band shows the maximum absorption band shift of around 4-5 nm which may be explained by the drug conjugation to the Fe3O4 nanoparticles. The spectrum indicates the formation of Fe3O4 magnetic nanoparticles having black color and obtained material is found with energy band gap (E) of 2.12 eV and 2.19 eV. On the basis of the findings from dynamic light scattering (DLS) results, it can be concluded that overall particle size of magnetic iron oxide nanoparticles is observed as 765 nm. In the present study the polydispersity index (P.I.) of bare Fe3O4 magnetic nanoparticles is 0.221, which indicate the hydrodynamic property of the synthesized particles.

How the Magnetization Angle of a Linear Halbach Array Influences Particle Steering in Magnetic Drug Targeting—A Systematic Evaluation and Optimization

The main challenge in magnetic drug targeting lies in steering the magnetic particles, especially in deeper body layers. For this purpose, linear Halbach arrays are currently in focus. However, to the best of the authors’ knowledge, the impact of the magnetization angle between two neighboring magnets in Halbach arrays has not been investigated for particle steering so far. Therefore, in this paper, a systematic numerical parameter study of varying the magnetization angle of linear Halbach arrays is conducted. This is completed by undertaking a typical magnetic drug targeting scenario, where magnetic particles have to be steered in an optimized manner. This includes the calculation of the magnetic flux density, its gradient, the total magnetic energy, and the resulting magnetic force based on a fitting function for the different Halbach constellations in the context of examining their potential for predicting the particle distribution. In general, increased magnetization angles result in an increased effective range of the magnetic force. However, as there is a trade-off between a weak force on the weak side of the array and a simple manufacturing process, a magnetization angle of 90∘ is recommended. For evaluating the steering performance, a numerical or experimental evaluation of the particle distribution is mandatory.

Contribution of rational design and fractional rheology on magnetic nanoparticle-based drug targeting in a microvessel with Saffman force

Magnetic nanoparticles based drug targeting is one of the prominent drug targeting methods due to non-invasive treatments, and recovery efficiency. The aim of the present problem is to analyze the trajectories of drug carrier particles and the total volume fraction of magnetic nanoparticles required for capturing purposes close to the tumor region. Due to the complex nature of blood, the viscoelastic Maxwell fluid relation is used to describe blood, and the flow of nanoparticles is investigated using momentum equations with the time-variant Caputo-Fabrizio fractional order expression to capture memory effects. The rational design of the nanoparticles such as size and shape with different aspect ratio along particle-particle interaction, Saffman force and external magnetic force are incorporated in the governing equation. The velocity profile of the fluid is represented in the form of the inverse of Laplace and Hankel transform. The velocity profile is solved by numerical integration and trajectories of the drug carrier particles analyzed by using the fourth order Runge-Kutta method by developing an algorithm. The conclusion drawn from the study shows that drug carriers lead towards the tumor region with long term memory effects, and it is easily captured at the tumor region. Viscoelastic rheology capture possibly opposes the drugs carrying magnetic nanoparticles to capture at tumor regions following a similar phenomenon by Saffman force. Spherical shaped drugs carrying magnetic nanoparticles are more prominent to be targeted to the tumor region than other shaped drugs carrying magnetic nanoparticles. The present study will help biomedical engineers and nanomedicine researchers develop magnetic devices and the next generation of drug carrier particles to treat cancerous tumors.

Pulsatile blood flow simulations of magnetic drug targeting (MDT) for drug particles dispersion through stenosis asymmetric and symmetric vessels

Magnetic drug delivery has emerged as an innovative strategy for addressing medical conditions like tumors and vascular occlusions. In this study, we delve into the influence of magnetic fields on three-dimensional models representing various vessel configurations, including unobstructed, asymmetric, and symmetric vessels. We take into account critical factors such as non-Newtonian viscosity, pulsatile flow, and the presence of vessel obstructions. By investigating drug particles ranging from 1 to 4 µm in diameter, our findings illuminate the central role that magnetic particles play in Magnetic Drug Targeting (MDT). Importantly, we observe a substantial enhancement in drug particle capture efficiency in the presence of a magnetic field, particularly for larger particle diameters. Nevertheless, this efficiency saturates at 100% for diameters exceeding 3 µm due to particle–wall interactions. Interestingly, within potential obstruction areas, particle capture efficiency exhibits a nuanced relationship with diameter. Even at a diameter of 4 µm, the magnetic field's influence on vessel walls leads to particle capture before reaching obstructions, thus reducing efficiency. Comparing scenarios without a magnetic field, it is found that symmetrical obstructions yield higher capture efficiency compared to asymmetrical vessels, and asymmetric vessels outperform their smoother counterparts. Moreover, the presence of vessel obstructions amplifies drug particle capture efficiency. Consequently, our simulations unveil significant potential for the application of MDT in the treatment of atherosclerosis. From a physics perspective, these results offer promising prospects for the application of Magnetic Drug Targeting in the realm of cardiovascular diseases.

Magnetic feature and regression analysis of Reiner-Philippoff boundary layer flow

The design and optimization of magnetic fluid-based processes, such as magnetohydrodynamic power generation and magnetic drug targeting, have become significant in recent times. To understand the magnetic and radiation features, as well as the sensitivity of engineering physical quantities to each dimensionless parameter in fluid flow, the Reiner-Philippoff (RP) fluid is best suited in this instance, as it exhibits shear-thickening, shear-thinning, and Newtonian behavior. The non-similar transformation is used to transform the partial differential equations that describe the flow into two-variable differential equations. The transformed dynamical equations are solved numerically using a spectral-based numerical technique; namely, the bivariate simple iteration method (BSIM). The effects of magnetic field strength and radiation parameter on the stretching and shrinking sheets are examined. The investigation reveals that both the magnetic field strength and radiation parameter have a significant impact on the flow behavior and rate of heat transfer. For the radiation parameter R∈[0,0.5], the skin friction coefficient and Nusselt number increase by 22.6% and 5.98%, respectively. Additionally, an 100% increment in Prandtl parameter reduces the Nusselt number by 287.36%. Regression analysis is performed to identify the most significant parameter affecting the engineering quantities. The results show that the Bingham constant, γ, is the only parameter that is not significant on the skin friction coefficient, while all the parameters have significant impact on the Nusselt number. The findings in this study have important implications in the biomedical industry, the design of machines, and the fourth industrial revolution.

Folic acid-coupled bovine serum albumin-modified magnetic nanocomposites from quantum-sized Fe3O4 and layered double hydroxide for actively targeted delivery of 5-fluorouracil

The development of multifunctional magnetic nanocomposites as a drug delivery system for cancer therapy is highly desirable in current nanomedicine. Herein, folic acid-bovine serum albumin conjugate (FA-BSA) was modified on nanocomposites by combining quantum-sized Fe3O4 and layered double hydroxide (LDH) to obtain a novel FA-BSA/Fe3O4@LDH for the delivery of the anticancer drug 5-Fluorouracil (5-Fu). The prepared nanocomposites showed good dispersibility, colloidal stability, magnetic property and erythrocyte compatibility. FA-BSA/Fe3O4@LDH/5-Fu showed pH responsiveness, with both the amount and duration of release of FA-BSA/Fe3O4@LDH/5-Fu being significantly higher in pH 5.0 release medium than in pH 7.4 release medium. The cellular experiments implied that no significant cytotoxicity of FA-BSA/Fe3O4@LDH, particularly due to the presence of FA-BSA, which further enhanced the biocompatibility of the nanocomposite. Furthermore, FA-BSA/Fe3O4@LDH/5-Fu could specifically target the 2D HepG2 cells model and 3D hepatoma cell microspheres model in vitro, and efficient internalization through folate receptor-mediated endocytosis, showing excellent anti-cancer cell activity in a concentration-dependent manner. Therefore, the constructed FA-BSA/Fe3O4@LDH was able to provide a potential novel multifunctional nanocomposite for magnetic-targeting drug delivery and pH-responsive release of drugs to enhance the efficiency of cancer therapy.

Evaluation of a temperature-responsive magnetotocosome as a magnetic targeting drug delivery system for sorafenib tosylate anticancer drug

In this investigation, a polymeric fusion of chitosan (CS) and thermosensitive poly (N-isopropyl acrylamide) - PNIPAAm - encapsulated a magnetotocosome, biocompatible nanocarrier. This encapsulation strategy demonstrated improved drug entrapment efficiency, achieving up to 98.8 %. Additionally, it exhibited extended stability, optimal particle dimensions, and the potential for industrial scaling, thus facilitating controlled drug delivery of sorafenib tosylate to cancerous tissue. Reversible Addition-Fragmentation Chain Transfer (RAFT) techniques were employed to synthesize PNIPAAm. The effects of polymer molecular weight and polydispersity index on the lower critical solution temperature (LCST) were evaluated. The resulting polymeric amalgamation, involving the thermosensitive PNIPAAm synthesized using RAFT techniques and CS that coated the magnetotocosome (CS-Raft PNIPAAm-magnetotocosome) with an LCST approximately at 45 °C, holds the potential to enhance drug bioavailability and enable applications in hyperthermia treatment, controlled release, and targeted drug delivery.

Cell migration-inspired stochastic steering strategy of magnetic particles in vascular networks

One primary challenge of magnetic drug targeting is to achieve the efficient and accurate delivery of drug particles to the desired sites in complex physiological conditions. Though a majority of drugs are delivered through intravenous administration, until now, the kinematics and dynamics of drug particles influenced by the magnetic field, vascular topology, and blood flows are still less understood. In this work, a multi-physics dynamical model, which captures transient particle motions inside the vascular networks manipulated by the external magnetic field, is developed. Based on the model, we studied the transport efficiency of particles in the two-dimensional (2D), three-dimensional (3D) artificial, and in vivo-relevant vascular networks. It is found that particles that perform a random walk with correlated speed and persistence, recapitulating some characteristics of migratory motion of immune and metastasis cells, have the largest mean square displacements in various vascular network topologies. Next, we designed a stochastic magnetic steering strategy, using a time-varying gradient magnetic field, to manipulate particles to perform the cell migration-inspired random motions in the vasculature. The capability of the proposed steering strategy to improve the particle spreading speed and reduce the consumed magnetic energy has been demonstrated using our multi-physics numerical model. Furthermore, the influence of heterogeneous flows in the vascular networks on the particle steering efficiency was investigated. Overall, the numerical model and the proposed stochastic magnetic steering strategy can be used to assist the development of drug delivery systems for precise medicine research.

Activation of energy in MHD Casson nanofluid flow through a porous medium in the presence of convective boundary conditions and suction/injection

Casson fluids are used to understand the rheological characteristics of pigment-oil suspensions, polymeric gels, emulsions, heavy oil, etc. Hence in this article, numerical work is carried out to investigate a steady MHD flow of a Casson nanofluid with the Cattaneo-Christov model over a stretching sheet in the presence of a porous medium with heat generation, and suction/injection. The effects of activation energy and chemical reactions are also considered. The concept of MHD is significant because of its numerous applications, including power generators, cooling process, sensors, and magnetic drug targeting. The governing equations of the model are reduced to a system of nonlinear coupled ordinary differential equations by appropriate transformations and are solved numerically via the bvp5c MATLAB package. The effects of the pertinent parameters on the velocity, temperature, and fluid concentration fields along with the skin friction, heat, and mass transfer rates are discussed in detail through figures and tables. It is reported that the velocity field decreases with an escalation in the magnetic field, porosity, and suction. However, the heat transfer rate enhances due an enhancement in suction and the Biot number, whereas it declines with the increasing values of the Brownian motion, thermophoresis, heat generation and thermal relaxation parameters. Furthermore, activation energy increases the fluid concentration.

A Two-Dimensional Transient Computational Multi-Physics Model for Analyzing Magnetic and Non-Magnetic Particle (Red Blood Cells and E. Coli Bacteria) Dynamics in a Traveling Wave Ferro-Magnetic Microfluidic Device for Potential Cell Separation and Sorting

Abstract This paper presents the theory and development, validation, and results of a transient computational multiphysics model for analyzing the magnetic field, particle dynamics, and capture efficiency of magnetic and nonmagnetic (e.g., Red Blood Cells and E. Coli bacteria) microparticles in a traveling wave ferromagnetic microfluidic device. This computational model demonstrates proof-of-concept of a method for greatly enhancing magnetic bioseparation in ferromicrofluidic systems using an array of copper conductive elements arranged in quadrature to create a periodic potential energy landscape. In contrast to previous works, our approach theoretically uses a microfluidic device with an electronic chip platform consisting of integrated copper electrodes that carry currents to generate programable magnetic field gradients locally. Alternating currents are applied to the electrodes in quadrature (using a 90 deg phase change from the neighboring electrode) to create a periodic magnetic field pattern that travels along the length of the microchannel. Our previous work evaluated magnetic and nonmagnetic particles in a static magnetic field within the same channel geometry. This work is a phase 2 study that expands on the previous work and analyzes the dynamics of magnetic and nonmagnetic entities characterized by material magnetic susceptibility in a transient magnetic field. This is an improvement over our previous work. The model, which is described in more detail in the methods section, combines a Eulerian-Lagrangian and two-way particle-fluid coupling CFD analysis with closed-form magnetic field analysis that is used to predict magnetic separation considering dominant magnetic and hydrodynamic forces similar to our previous works in magnetic drug targeting. The model was also validated with an experimental low frequency stationary flow study on separating nonmagnetic latex fluorescent particles in a water based ferrofluid. The results from the experimental study and the developed model demonstrate that the proposed device may potentially be used as an effective platform for microparticle and cellular manipulation and sorting. The developed multiphysics model could potentially be used as a design optimization tool for traveling wave ferromicrofluidic devices.

Unsteady nano-magnetic drug dispersion for pulsatile Darcy flow through microvessel with drug elimination phenomena

Drug delivery by nano-drug carriers in magnetic drug targeting has shown a promising future in various cancer tumor treatments. The distinguishing properties of nanocarriers, such as small size, selective targeting, controlled release, and others, have made them more effective than the existing conventional treatments. However, several factors affect its delivery. In the present problem, we study the unsteady dispersion of drug-loaded magnetic nanocarriers in microvessels driven by a pulsatile pressure gradient derived from the unsteady Darcy law. Both fluid flow rate and mean velocity are computed analytically. The finite difference method is used to obtain the numerical solution of the solute transport equation, and the results are presented in graphs. Our results show that not only does the Womersley number influence the pulsatility dispersion of nanocarrier particles but also the microvessel permeability, magnetic-tumor distance, magnetization number, and volume fraction of magnetic nanoparticles. We found a drop in drug-loaded magnetic nanocarriers' concentration at the targeted site with decreasing blood pulsatility in the microvessel as portrayed by the Womersley parameter. In contrast, the descending magnetic tumor distance promotes nanoparticle concentration in the tumor tissue. Furthermore, the effects of other parameters, such as permeability, magnetization, volume fraction of magnetic nanoparticles, source term, elimination parameter, and nanocarrier radius, are discussed. To sum up, based on the Womersley frequency parameter coefficient used to describe blood pulsatility resulting from forceful heartbeat, flow pulsatility and nanocarrier particle dispersion are positively correlated, while magnetic-tumor distance is negatively correlated with both pulsatility and nanoparticle concentration.