Fumihito Mishima

Three Dimensional Motion Control System of Ferromagnetic Particles for Magnetically Targeted Drug Delivery Systems

The development of a 3-dimensional (3-D) navigation system of ferromagnetic particles in a flow system was performed. In order to improve the practice of using externally-applied magnetic fields for targeting the magnetic particles to a circumscribed body region, we tested the feasibility of a novel 3-D navigation system, made by applying a strong external (magnetic) field through a GdBaCuO bulk superconductor. A 3-D theoretical model is proposed and used in order to evaluate the efficiency of the navigation/retention of magnetic particles in the flow system. Furthermore, an experimental model system was made and the efficiency of a prototype system was examined. Comparisons of experimental and the corresponding calculation results were made to examine the theoretical model system

A Study of Magnetic Drug Delivery System Using Bulk High Temperature Superconducting Magnet

A magnetic drug delivery system (MDDS) has been studied to navigate and/or accumulate the magnetic seeded drug at a local diseased part in the human body. The bulk high temperature superconductors (HTS) are employed to control the drug because they would produce the required magnetic fields for MDDS. The trajectory of the ferromagnetic particles in the blood vessel was calculated and the possibility of the navigation of the drug is discussed. In the experiment the HTS (GdBaCuO) which produces the magnetic field of 4.5 T at the surface, was located 25 mm apart from the Y-shaped blood vessel. The drug navigation probability to the desired direction was confirmed to be higher than 80%. A rat experiment was also performed successfully using a permanent magnet. The possible MDDS system will be discussed.

Development of Magnetic Field Control for Magnetically Targeted Drug Delivery System Using a Superconducting Magnet

We have been developing the device for magnetically targeted drug delivery system (MT-DDS), which can allow us to navigate and to accumulate the drug at the local diseased part inside the body by controlling to magnetic field strength and/or gradient generated by the superconducting magnets. In considering an application of this technique to the network of the blood vessel, a number of magnets should be placed within a small region. The magnetic field at the branching point is superimposed the fields from the magnets. The optimal arrangement of magnetic field for MT-DDS was calculated and experimental verification was made using several different sizes of Y-shaped glass tubes with multiple branching points as a model system of blood vessel. Ferromagnetic particles were injected into the Y-shape glass tube and were navigated by the magnetic field which was generated by the magnet optimally arranged based on the calculation. The ratio of the amount of the navigated ferromagnetic particle to the dosed amount was measured as magnetic navigation efficiency. It is found that experimental result of magnetic navigation efficiency agreed with the calculation results, which shows that magnetic navigation by the superconducting magnet can be a promising way for realization of MT-DDS.

Research and Development of Magnetic Drug Delivery System Using Bulk High Temperature Superconducting Magnet

The magnetic force control of the drug motion in the body has been studied in the current work. The calculation was made to study the possibility of the magnetic force control of the drag motion from outside of the body. The condition which enables the magnetic force control was clarified. The magnetic drug delivery system (MDDS) was demonstrated to be possible using the rat and permanent magnet and the validity of the calculation was confirmed by experiment. The magnetite suspension was introduced into a liver through portal vein in the rat experiment. A permanent magnet was used to navigate the magnetite. The navigation and accumulation of the magnetite was successfully performed. Based on the results, the MDDS experiment was made with an HTS magnet for a large-sized animal, pig. The HTS magnet of which size was 45 mm in diameter and 90 mm in length produced 5 T at 38 K. The suspension of the magnetite was injected into the blood vessel of the pig. It was confirmed that the magnetite was successfully navigated and/or accumulated by the HTS magnet.

Development of High Gradient Magnetic Separation System for a Highly Viscous Fluid

It is necessary to remove the metallic wear debris originating from pipe of manufacturing line in industrial plant processing highly viscous fluid such as foods or industrial products. In this study, we developed a high gradient magnetic separation (HGMS) system which consists of superconducting magnet and magnetic filters to remove the metallic wear debris. The particle trajectory simulation and the magnetic separation experiment were conducted with polyvinyl alcohol (PVA) as a model material of which viscosity coefficient was 1 Pa · s. As a result, maximum separation efficiency over 80% was achieved by optimization of experimental conditions such as mesh number, flow velocity and the number of filters.

Development of Magnetic Force-Assisted New Gene Transfer System Using Biopolymer-Coated Ferromagnetic Nanoparticles

Development of a simple method for converting the lipid envelope of an inactivated virus to a gene transfer vector was achieved a couple years ago in the medical school of Osaka University. Hemagglutinating virus of Japan (HVJ; Sendai virus) envelope (HVJ-E) vector was constructed by incorporating plasmid DNA into inactivated HVJ particles. This HVJ envelope vector introduced plasmid DNA efficiently and rapidly into various cell lines, including cancer cells and several types of primary cell culture. In the present study, efficiency of gene transfer was found to be greatly enhanced by application of a magnetic field. Therefore, we developed a new type of magnet for magnetically enhancing and targeting gene transfection system by using vectors associated with ferromagnetic particles coated with positively/negatively charged biopolymers, which can help to enhance and target gene delivery with higher efficiency. For the transfection experiment in vitro, the HVJ-E vector was mixed with ferromagnetic particles coated with biopolymer and this mixture was added to cultured cells which were set up under the permanent magnet. The effect of the dose of the ferromagnetic particles on the transfection efficiency was discussed. In order to clarify the effect of magnetic field gradient on the accumulation possibility of the magnetic particles and the accuracy of the targeted site in the blood vessels, calculation of the applied magnetic force for the ferromagnetic particles inside the blood vessel was also performed

Development of Magnetic Separation System for Powder Separation

The interfusion of impurities such as metallic wear debris has been a problem in the manufacturing process of foods, medicines, and industrial products. Gravity separation system and membrane separation system have been widely used for powder separation, however, sufficient separation rate was never achieved. Magnetic separation is a promising method to separate magnetic particles efficiently. Magnetic separation system under wet process is used conventionally, but it has some demerits such as necessity of drying treatment after separation and difficulty of running the system in the cold region. Thus, magnetic separation under dry process is prospective as an alternative method. In this paper, we developed High Gradient Magnetic Separation (HGMS) system under dry process. The present major problem of dry HGMS system is the blockage of magnetic filter caused by particle coagulation or deposition. To solve this problem, we developed the apparatus in which arrangement of magnetic filter is variable. Using this apparatus, we optimized the filter arrangement and achieved high separation efficiency of impurities from the mixed powder (0.1 wt% content of impurities) without blocking of filters.

Study on Decontamination of Radioactive Cesium From Soil by HTS Magnetic Separation System

By the accident of the Fukushima Daiichi Nuclear Plant, radioactive substances have been scattered in the environment. The decontamination of radioactive substances in the soils and the wreckage, and the volume reduction of contaminated waste are urgent issues. In this study, we examined the possibility for the soil decontamination of Cs-137, the main radioactive species with longer half-life, by means of the magnetic separation with a high-temperature superconducting magnet. We investigated the desorption behavior of the nonradioactive cesium from several kinds of clay minerals, and the removal rate by the ferromagnetic adsorbent from the aqueous phase. The results showed the possibility of the removal of cesium from the clay. Based on the results, we proposed a magnetic separation system of radioactive cesium by using high gradient magnetic separation with a superconducting magnet.

Removal of Iron Oxide With Superconducting Magnet High Gradient Magnetic Separation From Feed-Water in Thermal Plant

By the accident of Fukushima Daiichi Nuclear Plant, all the nuclear plants have stopped in Japan. As a result, the operation rate of thermal power plants has been increased. It caused growth in CO2 emission, which requires some kind of countermeasure. We focused on the iron oxide scales deposited on the piping system and boiler which declines the heat exchange efficiency of thermal power plants. In this study we attempt to remove the iron scales from the piping system and the boiler to maintain the power generation efficiency. In the current thermal plant treated by All Volatile Treatment (AVT) the iron elutes to the feed water in the low-temperature part which changes into iron ion or the paramagnetic fine iron oxide particles. On the other hand at the high-temperature part the main component of the scales is large ferromagnetic particles of magnetite. Therefore the magnetic separation at the high-temperature part is the more effective to remove the scale than that at the low-temperature part. For the reason, the existing method using the electromagnetic filter placed in the low-temperature part is not effective to remove the scales. We studied the high gradient magnetic separation (HGMS) at high-temperature part to remove a large amount of the scale. In this study, we assumed to install the HGMS system using the superconducting magnet at the inlet of the boiler.

Study on Decontamination of Contaminated Soils by Magnetic Separation

In this paper, we examined a new method for decontamination of soils by magnetic separation to reduce the volume of contaminated soils. In this method, we separate paramagnetic 2:1 type clay minerals with strong adsorbility of Cs ions from diamagnetic 1:1 type clay minerals with weak adsorbility of Cs ions. In addition, Cs ions desorbed from 1:1 types by washing are migrated to 2:1 type clay minerals. As a result, the doses of 1:1 type clay minerals can be reduced. First, it became apparent by the particle trajectory simulation that vermiculite, which is 2:1 type clay mineral, could be selectively separated by high gradient magnetic separation using superconducting magnet. Second, we confirmed the separation of vermiculite coexisting with kaolinite, which is 1:1 type clay mineral, by the experiments based on the simulation. Moreover, the experiments using the actual contaminated soils were conducted to examine the migration of Cs ions from 1:1 to 2:1 type clay minerals. As a result, it was observed that Cs ions desorbed from 1:1 types could be adsorbed to 2:1 type clay minerals when using 0.1 mol/L KI as wash solution. It showed the possibility of decreasing the dose of 1:1 type clay minerals.