Motion Of Nanoparticles Research Articles

Solidification performance improvement of phase change materials for latent heat thermal energy storage using novel branch-structured fins and nanoparticles

In the present study, we propose the combination of novel branch-structured fins and Al2O3 nanoparticles to enhance the performance of a phase change material (PCM) during the solidification process in a triple-tube heat exchanger. The inevitable drawback of PCMs is their lower heat conductivity, which can result in a long response time during the phase change process in latent heat thermal storage systems. Therefore, any serious improvement strategy needs an optimized phase change process. A mathematical model for a two-dimensional structure composed of a PCM with paraffin RT82 and Al2O3 nanoparticles that considers the thermal conduction in metal fins, Brownian motion of nanoparticles, and natural convection in a liquid phase PCM is proposed and verified based on experimental results. The impact of various volume fractions and fin layouts on the solidification process is discussed, involving the evolution and deformation of solid–liquid interfaces and distribution of isotherms and average temperature and liquid fraction curves. The results imply that the solidification behaviour can be significantly enhanced by the application of nanoparticles and metal fins. Compared with the inherent structure of the heat exchanger, the solidification time is decreased by 8.5%, 9.3%, and 10.3% for Al2O3 nanoparticles (at 2%, 5%, and 8%, respectively) only and by 83.0%, 80.7%, 80.8%, and 82.9%, respectively, for various fin layouts only. This is attributed to increased heat transfer by thermal conduction and natural convection. It can be concluded that the impact of the use of fins is preferable compared to that for nanoparticles, and the benefit of nanoparticles is limited.

Investigation of Nanofluid Natural Convection Inside a Square Cavity for Two Orientations Using Lattice Boltzmann Method

In this study, natural convection heat transfer of a water based nanofluid inside a square cavity is numerically investigated for two different orientations of a wall-heated cavity. The enclosure is heated by applying a constant heat flux while cooled at ambient conditions. Lattice Boltzmann method (LBM) is used to simulate nanofluid natural convection. The Brownian motion of nanoparticles is considered. LBM simulation is validated by comparison with experimental and numerical results of the literature. The effect of Rayleigh number (Ra = 103, 104, 105, 106), Biot number (Bi = 0.1, 1, 10, 100) and volume fraction of nanoparticles (Φ = 0, 1, 3 and 5%) on the isotherms, streamlines, velocity components, local and Nusselt number is analyzed for two oriented cavities. The bottom-heated cavity shows higher heat transfer rate than that of the cavity heated from the sidewall. The average Nusselt number increases by up to 6.81%. Furthermore, Biot number, Rayleigh number, and volume fraction of nanoparticles show significant effects on the heat transfer rate.

Pyroelectric Janus nanomotors for synergistic electrodynamic-photothermal-antibiotic therapies of bacterial infections.

Antibacterial electrotherapy is currently activated by external electric field or self-powered generators, but usually needs complicated power management circuits. Herein, near-infrared illumination (NIR) of pyroelectric nanoparticles (NPs) produces a built-in electric field to address the effectiveness and safety concerns in the antibacterial treatment. Janus tBT@PDA NPs were obtained by capping polydopamine (PDA) on tetragonal BaTiO3 (tBT) NPs through defining the polymerization time, followed by ciprofloxacin (CIP) loading on the PDA caps to fabricate Janus tBT@PDA-Cip NPs. NIR illumination of PDA caps creates temperature variations on tBT NPs to generate photothermal and pyroelectric effects. Finite element simulation reveals a pyroelectric potential of over 1 V and sufficient reactive oxygen species (ROS) are produced to exhibit pyroelectric dynamic therapy (PEDT). The elevated temperature on one side of the Janus NPs produces thermophoretic force to drive NP motion, which enhances interactions with bacteria and overcomes limitations in the short action distance and lifespan of ROS. The pyroelectric field accelerates CIP release through weakening the π-π stacking and electrostatic interaction with PDA and also interrupts membrane potentials of bacteria to enhance CIP invasion into bacteria. The synergistic antibacterial effect of pyroelectric tBT@PDA-Cip NPs causes the fully recovery of S. aureus-infected skin wounds and regeneration of intact epidermis, blood vessels and hair follicles, while no obvious pathological change or inflammatory lesion is detected in the major organs. Thus, the pyroelectric Janus nanomotors demonstrate synergistic PEDT/photothermal/antibiotic effects to enhance antibacterial efficacy while avoiding the necessity of excessive heat, ROS and antibiotic doses. STATEMENT OF SIGNIFICANCE: : Antibacterial treatment is challenged by antibiotics-derived side effects and the evolution of resistant strains. Phototherapy is commonly associated with excessive heat and oxidative stress, and their combinations with other agents are especially encouraged to strengthen antibacterial efficacy while alleviating the associated side effects. Electric field is another activator to generate antibacterial abilities, but usually requires complicated power management and bulk electrodes, making it inconvenient in a biological setup. To address these challenges, we propose a strategy to generate microelectric field on nanoparticles themselves and achieve synergistic electrodynamic-photothermal-antibiotic therapies. The pyroelectric effect weakens interactions between nanoparticles and antibiotics to accelerate drug release, and the built-in pyroelectric field increases membrane fluidity to enhance bacterial uptake of antibiotics.

Hybrid-nanofluid mixed convection in square cavity subjected to oriented magnetic field and multiple rotating rough cylinders

In this study, mixed convective hybrid-nanofluid flow in a partially heated square cavity with two rotating rough cylinders in presence of an external magnetic field is numerically investigated. A pair of rotating rough cylinders is placed at different locations inside the cavity. The cavity is permeated by an external magnetic field at different inclination angles. Maxwell's thermal conductivity model is modified incorporating Brownian motion of hybrid nanoparticles. The conservation equations of the flow and thermal fields are simulated using finite element method. The effects of different influential parameters such as cylinders rotation velocity (0 ≤ ω ≤ 50), Hartmann number (0 ≤ Ha ≤50), hybrid nanoparticle volume fraction (0% ≤ φ ≤ 5%) and magnetic inclination angle (0° ≤ α ≤ 135°) on the flow and thermal fields are explored via streamlines, isotherms and bar charts of average Nusselt number. The simulated results ensure that mixed convective flow is accelerated with cylinders rotation speed but declines with higher magnetic field strength and hybrid-nanoparticle volume fraction. Heat transfer enhancement is recorded up to 261.29% at highest rotating speed of rough cylinders (ω: 0–50, φ = 1%, Ha = 10). Enhancement of heat transfer rate is found decreasing for increasing magnetic field strength. Lowest heat transfer rate is occurred at highest magnetic field impact (Ha = 50) which is 144.62% less than that of heat transfer in absence of magnetic field (Ha = 0). Optimum heat transfer is found for 5% hybrid nanoparticle volume fraction which is 101.2% more compared to base fluid water. The presence of triangular rough components accelerates the fluid flow and heat transfer rate significantly. In addition, 48.89% more heat transfer is obtained for rotating rough cylinders with triangular components compared to smooth cylinders. Moreover, maximum heat transfer is achieved at magnetic inclination angle of 90°. It is also observed that the flow and thermal fields strongly depend on the cylinders arrangements.

Pyroelectric Janus nanomotors to promote cell internalization and synergistic tumor therapy

The tumor diffusion and cell internalization are the major obstacles to improving delivery efficacy of therapeutic agents. External electric fields have shown strong effect on the cell membrane polarization and fluidity, but usually need complicated power management circuits. Herein, in situ generation of microelectric field on nanoparticles (NPs) is proposed to overcome these delivery barriers. Janus tBT@PDA-CPT NPs were developed through partially coating of polydopamine (PDA) caps on pyroelectric tetragonal BaTiO3 (tBT) NPs and then camptothecin (CPT) conjugation via disulfide linkages. For comparison, cBT@PDA-CPT NPs were prepared from non-pyroelectric cubic BaTiO3 (cBT) as control. Near-infrared (NIR) illumination on PDA caps of the Janus NPs produces asymmetric thermophoretic force to drive NP motion for tumor accumulation, deep tissue penetration and effective cell interaction. Photothermally created temperature variations on tBT NPs build pyroelectric potentials to selectively change the membrane potential of tumor cells other than normal cells and exhibit a dominated role in enhancing tumor cell internalization and cytotoxicity. The combination index analysis confirms the synergistic effect of pyroelectric dynamic therapy (PEDT), chemotherapy and photothermal therapy (PTT), leading to full inhibition of tumor growth and noticeable extension of animal survival at significant lower CPT doses. The mild PTT/PEDT, the reduced CPT dose and the selective toxicity to tumor cells have achieved favorable treatment safety after tBT@PDA-CPT/NIR treatment. Therefore, in response to the differences in membrane potentials and glutathione levels between tumor and normal cells, we have demonstrated a concise design to achieve thermophoresis-driven motion, pyroelectric potential-enhanced cell internalization and PTT/PEDT/chemotherapy-synergized antitumor treatment.

Nanoparticle-induced drag reduction for polyacrylamide in turbulent flow with high Reynolds numbers

• Nanoparticles enhance the drag reduction effect of polyacrylamide solution. • The drag reduction of nanoparticles and polyacrylamide is observed at Re over 6000. • The combination of nanoparticles with cationic polyacrylamide is optimized. • Nanoparticles act as nodes to protect the polymer chain from shear breaking. Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlying mechanism from the fluid dynamics viewpoint. The drag reduction effects of adding SiO 2 nanoparticles to various polymer polyacrylamide (PAM) solutions were examined in this work. The optimal combination of SiO 2 nanoparticles with cationic polyacrylamide was confirmed. Interestingly, the addition of SiO 2 nanoparticles to cationic polyacrylamide solution was shown to be quite efficient for reducing drag, but only at higher flow rates with Reynolds numbers more than 6000, below which the nanoparticle addition is even negative. The addition of SiO 2 nanoparticles to the PAM solution is supposed to play a dual role. The first is an increase in flow resistance caused by the Brownian motion of nanoparticles, while the second is a decrease in flow resistance caused by acting as nodes to protect the polymer chain from shear-induced breaking under high shear action. At optimal nanoparticle concentration and under higher Reynolds numbers, the later effect is dominant, which could improve the drag reduction performance of polymer drag reducers. Our work should serve as a guide for the application of natural gas fracturing, where the flow rate is frequently very high.

Versatile magnetic configuration for the control and manipulation of superparamagnetic nanoparticles

The control and manipulation of superparamagnetic nanoparticles (SP-MNP) is a significant challenge and has become increasingly important in various fields, especially in biomedical research. Yet, most of applications rely on relatively large nanoparticles, 50 nm or higher, mainly due to the fact that the magnetic control of smaller MNPs is often hampered by the thermally induced Brownian motion. Here we present a magnetic device able to manipulate remotely in microfluidic environment SP-MNPs smaller than 10 nm. The device is based on a specifically tailored configuration of movable permanent magnets. The experiments performed in 500 µm capillary have shown the ability to concentrate the SP-MNPs into regions characterized by different shapes and sizes ranging from 100 to 200 µm. The results are explained by straightforward calculations and comparison between magnetic and thermal energies. We provide then a comprehensive description of the magnetic field intensity and its spatial distribution for the confinement and motion of magnetic nanoparticles for a wide range of sizes. We believe this description could be used to establish accurate and quantitative magnetic protocols not only for biomedical applications, but also for environment, food, security, and other areas.

3D sympathetic cooling and detection of levitated nanoparticles

Cooling the center-of-mass motion of levitated nanoparticles provides a route to quantum experiments at mesoscopic scales. Here we demonstrate three-dimensional sympathetic cooling and detection of the center-of-mass motion of a levitated silica nanoparticle. The nanoparticle is electrostatically coupled to a feedback-cooled particle while both particles are trapped in the same Paul trap. We identify two regimes, based on the strength of the cooling: in the first regime, the sympathetically cooled particle thermalizes with the directly cooled one, while in the second regime, the sympathetically cooled particle reaches a minimum temperature. This result provides a route to efficiently cool and detect particles that cannot be illuminated with strong laser light, such as absorptive particles, and paves the way for controlling the motion of arrays of several trapped nanoparticles.

Experimental analysis of electrical field combining nanofluids to enhance the mixed convective heat transfer in the rectangular channel

Owing to the disadvantages of low thermal conductivity and large viscosity, the mixed convective heat transfer efficiency of transformer oil can not meet the cooling demand of transformer. Furthermore, the electrical field force could manipulate the motion of nanoparticles, so as to further strengthen the heat transfer of nanofluids. Therefore, the electrical field and nanofluid are combined in the present study to enhance the thermal performance for cooling transformer. Meanwhile, the effects of electrical field strength, the nanofluid concentration and heat flux on heat transfer as well as mechanism are discussed. Then, a semi empirical correlation is proposed by considering the effects of electrical field and nanoparticles. The result shows that the heat transfer is greatly strengthened up to 65% with the increment of the electrical fields, and there exists an optimal concentration of nanofluid for the best enhanced effect. According to the mechanism analysis, the electrical field force pulls nanoparticles to high potential area and the fluid molecules move with nanoparticles, which impacts the boundary layer. Then, disturbances of nanofluids increase and the boundary layer thickness is decreased. Thus, the boundary layer thickness is reduced and fluid disturbance is strengthened, which significantly enhances heat transfer. Moreover, the predicted values calculated by the semi empirical equations fit the experimental data well.

Brownian motion of poly(divinylbenzene) nanoparticles in water

Understanding the motion of nanoparticles in liquid is of practical importance for drug delivery and fluid flow in nanofluidic systems. In this work, we use a nanoparticle tracking analyzer to investigate the Brownian motion of polydivinylbenzene (PDVB) nanoparticles in water and a video camera to record the aggregation of PDVB aggregates on the water surface. Using water as the liquid medium precludes the possible complex interaction between the liquid medium and the PDVB nanoparticles, which can possibly alter the random characteristics of the motion of the PDVB nanoparticles. The diffusivity of the PDVB nanoparticles determined from the mean square displacements of the PDVB nanoparticles has the same activation energy as that for the intrinsic viscosity of the corresponding aqueous suspension of the PDVB nanoparticles. The correlation between the diffusivity for the motion of the PDVB nanoparticles in water and the intrinsic viscosity of the corresponding aqueous suspension follows the Stokes–Einstein relation. The capillary effect and the interaction between PDVB aggregates and the liquid media enable the aggregation of the PDVB aggregates on the water surface, which follows the first-order reaction with activation energy larger than that for the random motion of the PDVB nanoparticles in water.

Nanofluid containing motile gyrotactic microorganisms squeezed between parallel disks

Advanced nano and microtechnologies for nano/micro-electronic devices have made substantial advances in the past few years. These technologies are rapidly incorporating advanced fluid media such as nanofluids and biological microorganisms. Inspired by bio-nanofluid applications in medicine, biological systems and biotechnology in the present study, mathematical model is evolved for unsteady bio convective conducting nanofluid along with gyrotactic micro-organisms squeezed between parallel disks. The lower disk and upper disks are solids. The temperature field is improved by the methods of haphazard motion of nanoparticles and thermophoresis parameters. The nano-bio transfer model is written as a series of non-linear partial differential equations that are reduced into a set of ordinary differential equations using suitable transforms. The dimensionless problem is then numerically solved by RK-4th order scheme utilizing MATLAB bvp4c solver’s package to investigate the impact of the squeezing parameter, Hartman number, Brownian motion and thermophoresis parameter on motile microorganism velocity, temperature, nanoparticle concentration, and density. The friction factor, Nusselt number, Sherwood number and microorganism number distributions on Hartman number, thermophoresis and Brownian motion factors are also computed. The Brownian motion and the thermophoresis factors of nanoparticles cause an increment in temperature profiles for both suction and injection. The concentration and motile microorganism are both amplified for the Brownian parameter in the case of injection, whereas they are declined for suction and the opposite trend is observed for the thermophoresis parameter. The motile microorganism is deflated for both suction and injection with thermophoresis parameter. Suction and injection adversely affect the transfer properties at the disks. The resistive magnetic body force prevails in the core zone, resulting in a decrease in velocity. The heat generation in squeeze films with motile microorganisms can be successfully removed with magnetic nanoparticles which require a longer serviceability of the lubrication system, bio-medical systems and need for less maintenance and a longer lifespan approach. The finding is pertinent to novel bio-microsystems that combine nanofluid and the bioconvection phenomenon. The percentage increase in heat, mass, and microorganism transport rates is calculated.

Photothermal Propelling and Pyroelectric Potential-Promoted Cell Internalization of Janus Nanoparticles and Pyroelectrodynamic Tumor Therapy.

Cancer phototherapy experiences limitations in tissue diffusion and cell internalization of phototherapeutic agents and dose-dependent side effects. Herein, Janus pyroelectric nanoparticles (NPs) are designed to generate self-powered motion and built-in electric fields to overcome the delivery barriers. Polydopamine (PDA) layers are partially coated on tetragonal BaTiO3 (tBT) NPs to prepare Janus tBT@PDA, and Au NPs are deposited on the PDA caps to obtain Janus tBT@PDA-Au NPs. Near-infrared (NIR) illumination of tBT@PDA-Au builds in situ pyroelectric potentials on NPs, which selectively affect the membrane potential of tumor cells rather than normal cells to enhance tumor cell internalization and produce reactive oxygen species (ROS) for pyroelectric dynamic therapy (PEDT). The asymmetric photothermal effect of the Janus NPs creates thermophoretic force to propel NP motion, which enhances tumor diffusion and cellular uptake of NPs and boosts cytotoxicity and intracellular ROS levels. The inoculation of Au NPs increases the photothermal effect, exhibits larger motion velocities, produces higher pyroelectric potentials, and elevates cellular uptake rates, resulting in significant induction of tumor cell apoptosis, suppression of tumor growth, and extension of animal survival. Thus, the concise design of tBT@PDA-Au/NIR treatment has achieved thermophoretic motion-promoted tissue diffusion, built-in electric field-enhanced cell internalization, and photothermal/PEDT-synergized antitumor efficacy.

Characterization of laser-induced optothermal effect in magnetic fluids based on a coreless-fiber-coupled microcavity Mach-Zehnder interferometric sensor

We present an integrated coreless-fiber-coupled microcavity Mach-Zehnder interferometric sensor to investigate the optothermal effect of magnetic fluids in the near-infrared wavelength region. The Brownian motion of magnetic nanoparticles and solvent molecules intensifies along with the change of medium refractive index under 473 nm laser illumination, and consequently the interference wavelengths are sensitive to the applied laser power. The maximum wavelength tuning sensitivity is up to 4.7475 nm/(mW/mm2) at a microcavity length of 262.26 µm. Based on interferometric spectral analysis, the refractive index sensitivities of the magnetic fluids are found to be about −3.0909 × 10-4 RIU/(mW/mm2) and −3.3319 × 10-4 RIU/(mW/mm2) for the laser power increase and decrease processes, respectively. The slight difference between the refractive index sensitivities could be attributed to the accumulation of laser energy and Sorét effect. The work presented in this paper provides important references for understanding the optothermal mechanism of magnetic fluids and the design of magnetic-fluids-functionalized laser-controlled photonic devices.

Heat transfer characteristics of nanofluid under the action of magnetic field based on molecular dynamics and flow states

Theoretical analysis, numerical simulations, and experimental studies are used to comprehensively investigate the changes in the heat transfer characteristics of Fe3O4–water magnetic nanofluid under different types of magnetic fields and the heat transfer mechanism, providing new ideas for its practical application. By combining the fundamental conservation theorem and the Boussinesq approximation, dimensionless control equations have been established. The analysis of the variation pattern of the calculated values of the source terms under different boundary conditions, as well as the order of magnitude analysis, concludes that: the enhanced trend of Brownian motion and thermophoretic motion is the main reason for the enhanced heat transfer capability of the magnetic nanofluid; where the thermophoretic motion contributes slightly more to the heat transfer; the increase in Joule heat is the reason for the further enhancement of the heat transfer capability by the magnetic field. Volume fraction, temperature, and magnetic field strength are positively correlated with the average convective heat transfer coefficient. The reason for magnetic fields to enhance heat transfer is revealed by the deflection of the magnetic nanofluid by the magnetic body flow under local magnetic fields to form localized reflux. The alternating magnetic field further enhances the ability of magnetic fields to enhance heat transfer in magnetic nanofluids. Overall, the effect of the applied magnetic field on the motion of the magnetic nanoparticles causes the disruption of the thermal boundary layer, which is responsible for the enhanced heat transfer capacity of magnetic nanofluids.

All-optical separation of chiral nanoparticles on silicon-based microfluidic chips with vector exceptional points

Surface-enhanced all-optical separation of chiral molecules plays an important role in the field of chiral recognition. However, the originally designed photonic micro/nano-structures are always suffering from a lot of limitations, such as low strengths of chiral optical forces, limited spatial resolutions, and narrow separation areas. Here, we theoretically design a silicon-based microfluidic chip to achieve highly efficient separations of chiral nanoparticles. By breaking the mirror-symmetry of a pair of lossy waveguides, two original orthogonal modes are coupled with each other, triggering the formation of a vector exceptional point. Numerical simulations clearly show that the superchiral gradient field can be generated in the microfluidic chip assisted by the vector exceptional point. Such a surface-enhanced chiral gradient field can induce extremely strong chiral gradient forces, pushing nanoparticles with opposite chirality toward different sides of the extended slot. Furthermore, we construct cascade vector exception points in a single microfluidic chip to fulfill the chiral separation with a larger spatial distance. Based on particle tracking simulations, we numerically demonstrate the feasibility and efficiency of our designed microfluidic chips under the influence of the thermal motion of nanoparticles. Our work proposes an efficient way of separating enantiomers in microfluidic chips with high spatial resolution, and shows an exciting prospect for next-generation chiral separation technologies.

Quasilinear Hyperbolic Systems Applied to Describe the Magnetohydrodynamic Nanofluid Flow

This study examines the flow of hyperbolic nanofluid over a stretching sheet in three dimensions. The influence of velocity slip on the flow and heat transfer properties of a hyperbolic nanofluid has been investigated. The partial differential equations for nanoparticle solid concentration, energy, and motion were turned into ordinary differential equations. Nanoparticle mass fluxes at boundaries are assumed to be zero, unlike surface concentrations. The influence of the main parameters on flow characteristics, surface friction coefficients, and the Nusselt number has been visualized. The results suggest that Brownian motion has a negligible impact on the heat transfer rate. The ratio of the elastic force to the viscosity force was found to decrease the fluid velocity. The resulting thermophysical properties of nanofluids are in agreement with previous research. The present findings can be used to expand the potential for using nanofluids as a coolant in critical thermophysical and industrial installations.

Analysis of the Thomson and Troian velocity slip for the flow of ternary nanofluid past a stretching sheet

In this article, the flow of ternary nanofluid is analysed past a stretching sheet subjected to Thomson and Troian slip condition along with the temperature jump. The ternary nanofluid is formed by suspending three different types of nanoparticles namely text{TiO}_{2}, text{Cu} and text{Ag} into water which acts as a base fluid and leads to the motion of nanoparticles. The high thermal conductivity and chemical stability of silver was the main cause for its suspension as the third nanoparticle into the hybrid nanofluid text{Cu-TiO}_{2}/text{H}_{2} text{O}. Thus, forming the ternary nanofluid text{Ag-Cu-TiO}_{2}/text{H}_{2} text{O}. The sheet is assumed to be vertically stretching where the gravitational force will have its impact in the form of free convection. Furthermore, the presence of radiation and heat source/sink is assumed so that the energy equation thus formed will be similar to most of the real life applications. The assumption mentioned here leads to the mathematical model framed using partial differential equations (PDE) which are further transformed to ordinary differential equations (ODE) using suitable similarity transformations. Thus, obtained system of equations is solved by incorporating the RKF-45 numerical technique. The results indicated that the increase in the suspension of silver nanoparticles enhanced the temperature and due to density, the velocity of the flow is reduced. The slip in the velocity decreased the flow speed while the temperature of the nanofluid was observed to be increasing.

Computer Simulations of EMHD Casson Nanofluid Flow of Blood through an Irregular Stenotic Permeable Artery: Application of Koo-Kleinstreuer-Li Correlations.

A novel analysis of the electromagnetohydrodynamic (EMHD) non-Newtonian nanofluid blood flow incorporating CuO and Al2O3 nanoparticles through a permeable walled diseased artery having irregular stenosis and an aneurysm is analyzed in this paper. The non-Newtonian behavior of blood flow is addressed by the Casson fluid model. The effective viscosity and thermal conductivity of nanofluids are calculated using the Koo-Kleinstreuer-Li model, which takes into account the Brownian motion of nanoparticles. The mild stenosis approximation is employed to reduce the bi-directional flow of blood to uni-directional. The blood flow is influenced by an electric field along with a magnetic field perpendicular to the blood flow. The governing mathematical equations are solved using Crank-Nicolson finite difference approach. The model has been developed and validated by comparing the current results to previously published benchmarks that are peculiar to this study. The results are utilized to investigate the impact of physical factors on momentum diffusion and heat transfer. The Nusselt number escalates with increasing CuO nanoparticle diameter and diminishing the diameter of Al2O3 nanoparticles. The relative % variation in Nusselt number enhances with Magnetic number, whereas a declining trend is obtained for the electric field parameter. The present study's findings may be helpful in the diagnosis of hemodynamic abnormalities and the fields of nano-hemodynamics, nano-pharmacology, drug delivery, tissue regeneration, wound healing, and blood purification systems.

Nano-particles carried by multiple dynein motors self-regulate their number of actively participating motors.

The application of nanotechnology in medicine is expected to spread rapidly. Many substances are now being researched for drug delivery and, more especially, cancer therapy and dealing with various viruses such as HIV, Herpes simplex virus, and adenoviruses. Since it is the center of gene maintenance and expression regulation, the cell nucleus is a valuable target for viruses of the type outlined above as well as drug delivery systems. The microtubule-associated motor protein dynein is primarily responsible for spontaneously occurring intracellular transport to the nucleus. In this case, we are inspired by viruses (for example, HIV) that recruit dyneins to actively move towards the nucleus. This type of transport is known as “active transport,” and it is distinguished by its directionality and persistence motion toward the nucleus, making it more effective... In this project we aim to mimic the highly efficient transportation properties of native cargoes by rationally designing universally decorated nano-particles (NPs) that could be used for drug delivery applications. We investigate the motion of artificial NPs which grafted with flexible polymers, each ending with a nuclear localization signal (NLS) peptide, thereby allowing recruitment of mammalian cytoplasmic dynein. This unique NP can self-regulate the number of participating dynein motor proteins to optimize their motility properties - engendering persistent motion towards the cell nucleus while being able to go around obstacles that are abundant in the cytoplasm or on the microtubules. Based on these benefits, the use of active transport rather than passive transport has a promising future for therapeutic reasons, both in terms of treatment efficiency and reduced side effects, as the amounts of drug/DNA necessary for therapy are reduced.

How Do Colloidal Nanoparticles Move in a Solution under an Electric Field?: In Situ Light Scattering Analysis.

Understanding the dynamics of colloidal nanoparticles (NPs) in a solution is the key to assembling them into solids through a solution process such as electrophoretic deposition. In this study, newly developed in situ analysis with light scattering is used to examine NP dynamics induced by a non-uniform electric field. We reveal that the symmetric directions of moving NP aggregates are due to dielectrophoresis between the cylindrical electrodes, while the actual NP deposition is based on the charge of NPs (electrophoresis). Over time, the symmetry of the dynamics becomes less evident, inducing feeble deposition as the less-ordered dynamics become stronger. Eventually, two separate deposition mechanisms emerge as the deposition rate decreases with the change in the NP dynamics. Furthermore, we identify the vortex-like NP motion between the electrodes. These in situ analyses provide insights into the electrophoretic deposition mechanism and NP behavior in a solution under an electric field for fine film construction.