阅读说明：本技术 用于使用体内可磁化装置测量和灭活病原体的方法和设备 (Method and apparatus for measuring and inactivating pathogens using in vivo magnetizable devices ) 是由 欧文·N·温伯格 于 2020-06-12 设计创作，主要内容包括：本发明涉及用于使用体内可磁化装置测量和灭活病原体的方法和设备。本发明提供了用于在磁性颗粒内收集和灭活病原体(例如冠状病毒)以减少体内活性病原体的数量的设备和方法。(The present invention relates to methods and apparatus for measuring and inactivating pathogens using an in vivo magnetizable device. The present invention provides devices and methods for the collection and inactivation of pathogens (e.g., coronaviruses) within magnetic particles to reduce the number of active pathogens in the body.)

1. An apparatus for inactivating or destroying at least one pathogen in a body, the apparatus comprising:

at least one magnetic actuator outside the body, the at least one magnetic actuator comprising at least one device comprising at least one inner portion and at least one magnetizable material,

wherein the pathogens are drawn into and damaged or destroyed within an interior portion of the device.

2. The apparatus of claim 1, wherein the pathogen is drawn into an interior portion of the device by an attractive force generated at least in part by actuation of the particles under the influence of a magnetic field generated by the magnetic actuator.

3. The apparatus of claim 1, wherein the pathogens inhaled in the interior portion of the device are inactivated, destroyed, or damaged by heat generated by a magnetizable component of the device, wherein the heat is generated by electromagnetic radiation emitted by an electromagnetic actuator or antenna outside the body.

4. The apparatus of claim 1, wherein the pathogens in the interior portion of the device are inactivated, destroyed, or damaged by shear or other mechanical forces actuated by magnetic or electromagnetic radiation emitted by an electromagnetic actuator or antenna in vitro.

5. The apparatus of claim 1, wherein the presence or absence of the pathogen in the device is sensed using an electromagnetic actuator or antenna external to the body.

6. The apparatus of claim 1, wherein the device is biodegradable in vivo.

7. The apparatus of claim 1, wherein the pathogen is a microorganism or a cell.

8. The apparatus of claim 1, wherein the device is magnetically barcoded.

9. The apparatus of claim 1, wherein at least a portion of the device is at least partially toxic to or at least partially sensitive to the pathogen.

10. The apparatus according to claim 1, wherein the portions of the device attract each other over sub-micron distances under the magnetic field from an actuator outside the body, thereby causing inactivation of the pathogenic substance.

Technical Field

The disclosed embodiments relate to methods and apparatus for inactivating pathogens in vivo using magnetizable materials.

Background

It is known that timely administration of materials that bind toxic chemicals can reduce the extent of disease by reducing the concentration of these toxic chemicals in the body. For example, activated carbon is often recommended after ingestion of toxic substances, and ethylenediaminetetraacetic acid (EDTA) is recommended after lead poisoning.

Some pathogens can bind to certain compounds (known as "receptors"). For example, a publication entitled "Structural basis for human coronavirus attachment to systemic acid receptors" in journal Nature structure & Molecular Biology, 2019, by m.a. tortorici et al teaches that coronaviruses bind to 9-0-sialic acid acetylation.

Certain pathogens (e.g., amoebas) can be attracted by compounds as taught in an article entitled "Human Tumor Necrosis Factor a Chemoattractant for the Parasite Entamoeba histolytica" by S.Blazquez et al in journal Infection and Immunity in 2006.

Furthermore, it is known that certain Cancer Cells can be attracted by compounds, as taught by c.e. green et al in an article entitled "Chemoattractant signalling between Cancer Cells and Macrophages regulations Cancer Cell differentiation," in the 2009 journal PLOS Biology.

Furthermore, it is known that magnetic particles can be administered to humans, and that magnetic particles can contain and release drugs or other compounds. It is known that the magnetic properties of these particles can be advantageously exploited by applying a magnetic field to the body, so that the particles preferentially accumulate at certain locations.

When nanoparticles are bound to chemicals, magnetic instruments can be used to detect changes in state in magnetic nanoparticles as taught by a. tomitaka et al in a paper entitled "Dynamic magnetic characteristics and magnetic particle imaging enhancements of magnetic-gold core-shell nanoparticles" in Nanoscale of 2019.

Furthermore, magnetic instruments can be used to detect the distance between portions of magnetic particles, as taught in the fast report entitled "Shape-changing magnetic assemblies as high-sensitivity NMR-accessible nanoprobes" in Nature, 2008, by g.zahow, s.j.dodd and a.p.koretsky.

Disclosure of Invention

The disclosed embodiments provide devices and methods for the collection and inactivation of pathogens (e.g., coronaviruses) within magnetic particles to reduce the number of active pathogens in vivo.

Drawings

FIG. 1 illustrates an example of one of the various embodiments disclosed.

Fig. 2 provides an illustration of how the device of fig. 1 may be used in a body 210.

FIG. 3 illustrates operations of one example of the disclosed embodiments in a method.

FIG. 4 shows another example of an embodiment of an apparatus provided in accordance with the disclosed embodiments.

FIG. 5 illustrates another embodiment of an apparatus provided in accordance with the disclosed embodiments.

Detailed Description

The disclosed embodiments provide apparatus and methods for collecting and inactivating pathogens (e.g., coronaviruses) within magnetic particles to reduce the number of active pathogens in vivo.

For the purposes of the present invention, the term "pathogen" is meant to include disease-causing microorganisms (e.g., viruses, bacteria, or fungi) as well as disease-causing substances (e.g., toxic substances, cytokines, kidney calcification, arterial plaque) or disease-causing cells (e.g., cancer cells or sickle cells). For clarity, the terms "particle" and "device" may be used interchangeably to refer to a component that is applied to the body, as "magnetic particle" is a term used by the public to mean a device or particle that contains a magnetizable material. The term "particles" does not mean that the device must be small. Rather, the width of the device may be 10 nanometers and the length 200 nanometers (potentially suitable for treating viruses), or the width and length may be up to several millimeters (potentially suitable for treating parasites). The term "fillable portion" of the device is intended to mean a space at least partially defined by components of the device, wherein the space can be filled with a fluid and/or a pathogen.

FIG. 1 shows an example of one of the various embodiments disclosed. The apparatus consists of a system comprising at least one device 100, the device 100 comprising a fillable part. As shown in fig. 1, the device 100 may be entirely hollow, or may be only partially hollow. The device 100 has a wall portion 110, which wall portion 110 may be gold or iron or other material. In fig. 1, the device appears cylindrical, however, it may be another shape with a hollow cross-section. The device 100 includes a material 120 that binds to pathogens such that the pathogens are temporarily or permanently retained within the device. Structures (e.g., polymers) such as 130 that elute chemoattractants or other chemicals for attracting pathogens may be included within or outside of the device. The apparatus 100 may comprise at least one magnetizable portion 150, on which magnetizable portion 150 a torque or a force may be exerted by a magnetic field. The apparatus 100 may comprise one or more additional magnetisable portions 140, on which magnetisable portions 140 a torque or force may be applied by means of a magnetic field.

Figure 2 shows how the device of figure 1 (now referenced 200) may be used in a body 210. The magnetic field 220 is generated by a coil or magnet or other electromagnetic actuator or antenna 230 outside the body. The electromagnetic actuator or antenna 230 may also be part of a system for imaging the body and/or the apparatus 100. Under operation of a computer (not shown), magnetic field 220 may manipulate device 200 in body 210 to a desired position in body 210 by applying a force on magnetizable portion 140 or magnetizable portion 150 of device 200. Magnetic field 220 may rotate device 200 by applying a torque on magnetizable portion 140 to better penetrate or otherwise pass through tissue within the body. The pathogen 240 may be attracted to the portion 130 and thereby drawn into the fillable portion of the device 200. Pathogen 240 may be immobilized in device 200 by binding to portion 120. The apparatus 200 may be heated to destroy or inactivate pathogens 240, for example by applying an external oscillating magnetic field using a coil or magnet 230 that heats the magnetisable portion 150 or by applying electromagnetic radio frequency radiation from an antenna (not shown) that may heat the walls 110 of the particles (which may be electrically conductive).

The above method operations of one example of the disclosed embodiments are shown in the flow chart of fig. 3. Although the term "subsequent operations" is used in the next portion of the description to describe the methods of the disclosed embodiments, it will be understood that some operations may be performed in a different order and may be repeated or omitted.

In operation 300, one or more particles (e.g., device 200) are administered to a body (e.g., orally or by inhalation or by intravenous injection). In a subsequent operation 310, the particles are optionally guided to a location of interest in the body, for example by applying a magnetic field 220. Alternatively, if the particles are coated with antibodies or other means that bind to one or more specific types of tissue, the particles may specifically accumulate, for example, at a location of interest. Or, alternatively, the particles may function anywhere in the body or in a subsystem (e.g., a circulatory subsystem of the body).

A subsequent operation 320 is attracting the pathogen into the fillable portion of the device.

Operation 330 is optionally detecting the pathogen, for example by altering the electromagnetic signal emitted by the particle in response to a changing magnetic field (as has been shown to be detectable with magnetic particle imaging).

In a subsequent operation 340, the pathogen may be inactivated, for example, by magnetically heating the particles or by rotating the particles to exert destructive shear forces on the pathogen or by rupturing the same by applying pressure on the pathogen. Alternatively, the particles may comprise a magnetoelectric material to which an electrical pulse may be applied to the pathogen.

In a subsequent operation 350, the particles may optionally be cleaned from the body, for example by allowing components of the particles to oxidize or be digested by tissues in the body and then excreted. These components are referred to as "biodegradable".

Fig. 4 shows another embodiment of the device, in which the device is designated by reference numeral 400. In this example, the walls 410 of the hollow device 400 are tapered such that when the device is rotated (e.g., by magnetic torque applied to the portion 440), suction is created by fluid (represented as black arrows) pulling the pathogen 460 into the fillable portion of the device 400. Pathogens 470 that have been pulled into the inflatable portion of the device can be inactivated or destroyed by shear forces or strong fluids or a combination of both or by heating the magnetic portion 440 or the magnetic portion 450 using magnetic induction. Components of healthy body 480 (e.g., small proteins) may pass through device 400 without injury. The sequence of operations undertaken using the embodiment of the apparatus shown in figure 4 is the same as or similar to the sequence shown in figure 3.

Fig. 5 shows another embodiment of the device 500 shown after application to the body and in the presence of a magnetic field (not shown in this figure) applied by a magnetic actuator located outside the body. Apparatus 500 includes anvil portions 530 and 510 (both of which contain magnetizable material) and a resiliently compressible portion 520 (which may be a polymer). The term "anvil" is used to imply a force being applied to a structure as employed by scientists attempting to apply high pressures to Diamond anvils (see, for example, an article entitled "Diamond and cell behavior up to 4 Mbar" published by b.li et al on PNAS in 2018). Due to the magnetic field already applied to the device 500 in the body, both the anvil part 530 and the anvil part 510 are magnetized and may be subjected to an attractive force on each other, thereby compressing and/or twisting or deforming the elastically compressible portion 520. The pathogen 540 is displayed nearby (e.g., within 10 microns). In case 550, the externally applied magnetic field has been reduced or eliminated by the external magnetic actuator, with the result that anvil portion 510 and anvil portion 530 are no longer attracted to each other and resiliently compressible portion 520 assumes a different configuration 560. The change in volume of fluid between the anvil portion 510 and the anvil portion 530 causes nearby fluid to flow into those spaces (fillable portions) between the anvil portion 510 and the anvil portion 530, drawing pathogens (now labeled 570) into the fillable portions. In condition 580, the magnetic field is again applied by the external actuator, thereby again compressing or twisting or bending the flexible portion (now designated with reference numeral 590), and pathogens 595 are crushed or twisted or otherwise damaged by the forces or torques applied by the anvil portion 510 and the anvil portion 530. The sequence of operations undertaken using the embodiment of the apparatus shown in figure 5 is the same as that shown in figure 3.

As described above, the apparatus of the disclosed embodiments may include an electromagnetic actuator 230 and at least one device 100, 200, 400, or 500 applied to the body 210. The body 210 may be a human, an animal, or even an inanimate object such as a river. The body contains pathogens 240, 460, 540. It is an object of the disclosed embodiments to destroy, destroy or inactivate pathogens. The electromagnetic actuator 230 may be used to manipulate the device 100, 200, 400, 500, and may also be used to provide images of the body 210 and particles 100, 200, 400, 500, as taught by i.n. weinberg in U.S. patent application 16/448,915 entitled "Method for Acquiring an Image and Manipulating Objects with Magnetic compositions Produced by One or More electromagnetic Arrays". Alternatively, imaging may be provided by a different instrument (e.g., an X-ray CT scanner), while manipulation, heating, and/or rotation of the apparatus 100, 200, 400, or 500 is achieved by a different magnetic system.

The walls 110 and 410 of the device and the resiliently compressible portion 520 may be organic (e.g., plastic), metallic (e.g., gold), silica, iron, or other material. It will be appreciated that manipulation of a device in the body using the external electromagnetic actuator 230 may be used to selectively position (or concentrate a plurality of such devices) the device at a desired location, tissue, portion or other part of the body (e.g., the lungs) or to selectively avoid positioning the device at a particular part of the body (e.g., the heart). It will be appreciated that heating and/or rotating or otherwise actuating the device in the body using an external actuator, as described with respect to fig. 2, may be used to selectively heat or rotate or otherwise actuate the device in a desired region of the body (e.g., the lungs) or to selectively avoid excessive or undesirable heating or rotation of the device in the body (e.g., the heart).

The devices 100, 200, 400, 500 may be manufactured according to a continuous operation using a template, as described by Irving Weinberg in a provisional patent application entitled "Method and Apparatus of Magnetic Micro-Syringes" (application No. 63011720).

As shown in fig. 1, the adhesive 120 and/or chemoattractant 130 can be bound to the particle by a linker, such as a gold-bound thiolate adsorption layer formed from dithiobis (succinimidyl propionate), as described in an article entitled "Low-level Detection of visual markers by a Surface-Enhanced Raman Scattering immobilized immunity" published in the 2005 journal anal. chem, j.d. driskell et al. It is understood that the adhesive and/or chemoattractant may also be placed within the particles shown in device 400 and device 500. As shown in fig. 1, the magnetizable portion 140 may be short so that it can be rotated by a helical magnetic field, while the magnetizable portion 150 may be longer to aid in the translation of the particles, as taught by l.o. mair et al in U.S. patent application 62/182,901 entitled "Method and Apparatus for Non-Contact Axial Particle Rotation and Decoupled Propulsion". It will be appreciated that similar long and short magnetic portions may also be placed within the particles shown in apparatus 400 and apparatus 500 to aid in transport. It will be appreciated that not all of the particles 100 need be rotated to cause the device 100 to apply suction and draw pathogens into the fillable portion of the device 100. For example, a portion of the interior or exterior of the particle 100 may be rotated and still apply suction. Alternatively, the particle 100 may have tendrils or other attached components, wherein the tendrils bind to the pathogens and draw the pathogens into the fillable portion of the particle as the particle 100 rotates or translates.

It will be appreciated that particles may be produced using a template-directed process, as taught by l.o. mair et al in U.S. patent application 62/292966 entitled "Roll-to-Roll manufacturing of organic particles using templates and electroplating". It will be appreciated that many particles 100, 200, 400 or 500 may be administered to the body, for example billions of particles per dose. It will be appreciated that the particles may be barcoded (by using, for example, magnetic elements 440, 450 of different lengths and thicknesses) so that the position of the particles within the body can be tracked. It is understood that the device 100, 200, 400 or 500 may be coated with one or more materials (e.g., polyethylene glycol) to make the device more biocompatible or less harmful to healthy tissue.

It will be appreciated that the use of the disclosed embodiments, as described above in the flowchart shown in fig. 3, may enable the selective use of the disclosed embodiments to eliminate or reduce the toxicity of one pathogen compared to another or to healthy tissue. For example, chemoattractant 130 may attract a particular cell or parasite. Or in another example, the internal dimensions of the device 400 may be of suitable dimensions to destroy 250nm virus without destroying smaller clotting factors in the blood. Or in another example as shown in fig. 5, the elastic portion 520 may be selected to be small enough to destroy 250nm viruses with compression without trapping or destroying smaller or larger structures, and large enough to contain 250nm viruses but not so large as to contain blood cells.

It will be appreciated that the profile of the wall 410 of the device 400 need not be a sharp taper as shown in fig. 4, but may be a different profile that creates suction as the device rotates. It is understood that the device 100, 200, 400, or 500 may have more than one interior portion to capture and damage pathogens.

The operation using the particles shown in fig. 4 is similar to the operation shown in fig. 3. In a first operation 300 (referring again to fig. 3), one or more particles (e.g., device 400) are administered to the body (e.g., orally or by inhalation). In a subsequent operation 310, the particles are optionally directed to a location of interest within the body. Alternatively, if the particles are coated with antibodies or other means that bind to one or more specific types of tissue, the particles may preferentially accumulate, for example, at a location of interest. Or alternatively, the particles may function anywhere in the body or in a subsystem (e.g., a circulatory subsystem of the body).

In a subsequent operation 320, the pathogen 460 is attracted by applying a magnetic field to rotate the particles 400 to create a suction force that pulls the pathogen into the interior of the device 400.

A subsequent operation 330 is to optionally detect the presence of a pathogen inside the device 400, for example due to the presence of the pathogen altering the electromagnetic signal emitted by the particles (as has been shown to be detectable by magnetic particle imaging) in response to the changing magnetic field.

In a subsequent operation 340, the pathogen may be inactivated, for example, by magnetic heating of the particles or by rotation of the particles to exert destructive shear forces on the pathogen or by the combined action of an electric current and the force exerted on the pathogen by the walls of the device. The destructive force may break the capsid or capsid of the pathogen and/or may disrupt the internal contents of the pathogen (e.g., genetic material, such as DNA or RNA). Note that these forces or inactivation operations may not be as effective on small materials (e.g., proteins), thereby increasing the selectivity of the device in inactivating pathogens (relative to components required or desired for health). Alternatively, the particles may comprise a magnetoelectric material that applies an electrical pulse to the pathogen.

In a subsequent operation 350, the particles may optionally be degraded within the body, for example by oxidation of the composition or digestion by tissues within the body.

The operation using the particles shown in fig. 5 is similar to that shown in fig. 3:

in a first operation 300 (referring again to fig. 3), one or more particles (e.g., device 500) are administered into the body (e.g., orally or by inhalation).

In a subsequent operation 310, the particles are optionally directed to a location of interest within the body. It will be appreciated that some or all of the magnetic content of the particles 500 may be made of various magnetic sub-portions that may be used to propel and rotate the particles 500 to a desired location deep within the body, such as taught by a. navev et al in an article entitled "Dynamic inversion optics to concentration magnetic rods to a central target" by Nano Letters in 2015. Alternatively, the particles may preferentially accumulate at the location of interest, for example, if the particles are coated with antibodies or other means that bind to one or more specific types of tissue. Or, alternatively, the particles may function anywhere within the body or in a subsystem (e.g., a circulatory subsystem within the body).

In a subsequent operation 320, the pathogen 540 is attracted by applying a magnetic field to compress the portion 520 and then ceasing the application of the magnetic field to release the compression to create a suction force that pulls the pathogen into the interior of the device 550.

Operation 330 then optionally detects the presence of pathogens within device 500, for example, as a result of the presence of pathogens that alter the electromagnetic signal emitted by the particles in response to changing magnetic fields, as taught, for example, by the fast report entitled "Shape-changing magnetic assemblies as high-sensitivity NMR-accessible nanoprobes," published by g.zahow, s.j.dodd and a.p.koretsky, Nature, 2008. This property may be useful in assessing viral load in the body, even possibly before the virus has the opportunity to infect cells and elicit a measurable response (e.g., using an antibody serum test).

In a subsequent operation 340, the pathogens may be inactivated or otherwise destroyed, for example by crushing the pathogens due to actuation of the particles by an externally located magnetic actuator. For example, the anvil 530 and anvil 510 may be attracted to each other creating a force that ruptures or otherwise harms the viral capsid, thereby exposing the genetic material within the capsid to the native enzymes, or to coatings on the anvil 530 or anvil 510 or portion 520, or to drugs or compounds eluted by these or other particulate structures. It is believed that a pressure of about 50 atmospheres can destroy the capsid as taught by A.Cordova in a paper entitled "Osmatic Shock and the Strength of Viral caps" in Biophysical Journal of 2003. A simple calculation of the magnitude of the force between two magnetic dipoles 250nm apart shows that it is many times higher than the force that small particles can withstand at 50 atmospheres. Alternatively, the pathogen may be inactivated by magnetic heating of the particles. It will be appreciated that some or all of the components of the apparatus 100, 200, 400, 500 may be coated with an insulating material to protect other structures within the body from such heating or electrical effects. Note that these forces or inactivation procedures may be less effective on small structures or components (e.g., proteins) within the body, thereby increasing the selectivity of the device in inactivating pathogens (as opposed to components required or desired for health). Alternatively, the particles may comprise a magnetoelectric material that applies an electrical pulse to the pathogen.

In a subsequent operation 350, the particles may optionally be degraded within the body, for example by oxidation of the composition or digestion by tissues within the body.

It will be appreciated that the powerful forces that the anvil may exert under the influence of the magnetic field established by the magnetic actuator deactivate pathogenic substances in the body. For example, the device may be used for eating soft or hard pathogenic structures that are otherwise difficult to remove, such as calcified plaque in an artery or kidney stone. In such embodiments, the anvil may be placed at the edge of the magnetic device and transported to a specific region (e.g., carotid, kidney, coronary) containing the pathogen material by the magnetic actuator 230. As described above, since the anvils are close to each other (e.g., less than 1 micron apart), the force generated by the attraction of the anvils is very strong.

It will be appreciated that the dumbbell configuration shown in fig. 5 is an example of a more generalized configuration that increases and decreases the internal volume of the anvil. One such structure may be a clamshell structure that is opened and closed by applying an external magnetic field to its clamshell components, stretching and compressing the support posts (e.g., portion 520).

It is to be understood that the term magnetic material refers to magnetizable materials, i.e. materials that have a magnetic moment during or after exposure to a magnetic field. It will be appreciated that the illustration of support columns (e.g., portion 520) is an example of a more generalized support structure, such as a compressible porous material or a set of compressible columns, which can contain viruses or other pathogens during expansion and transmit destructive forces or exert pressure on viruses or other pathogens during compression. The support structure or other elements (e.g., depending edges) of the dumbbell structure shown in fig. 5 can help retain viruses or other pathogens during the compression stage, for example, by capturing the viruses or other pathogens.

It is understood that the material compositions of the anvils 510 and 530 may be different from each other. This feature may be useful when applying various forces to the device, such as a repelling force to open the device after the device has stressed a pathogen. Repulsive forces can be achieved as taught by Nacev et al in an article entitled "Dynamic inversion enables to central magnetic rows to a central target" in Nano Letters 2015. The dynamic inversion method can be summarized as follows: shortly before the second magnetic pulse is applied to generate the force, a magnetic pulse is applied that polarizes the magnetic material in the desired direction. Since the initial polarization takes some time to decay, the same second magnetic pulse may affect different materials differently. If the anvil 510 and the anvil 530 are made of different materials, they can be attracted or repelled from each other by appropriately using the principle of dynamic inversion.

It is understood that genetic material is released after the shell or capsid or other protective coating of the pathogen is ruptured or otherwise damaged by the device, which can be destroyed by compounds (e.g., proteases) naturally occurring in the body. Alternatively or additionally, coatings or materials contained in (or eluted from) components of the devices 100, 200, 400, 500 may help to destroy such materials. For example, Iron oxide is known to have antiviral activity as taught in the Journal of Infection and Chemotherapy in 2019 by R.Kumar et al, entitled "Iron oxide nanoparticles activity of H1N1 underfluenza A virus".

The device 100, 200, 400, 500 may be cleaned by applying a magnetic force or torque from an external magnetic actuator. For example, rotation and/or translation of the device may be used to remove or replace material that may block or otherwise impair transport of pathogens into the device.

It will be understood that the term "pathogen that inhales the interior portion of the device" includes attraction of the pathogen to the chemoattractant, or binding of the pathogen to the binding sites 120 on the wall of the device (in which case the pathogen may have encountered the binding sites by diffusion), or inhalation of the pathogen into the rotating device or into the space between the cap structure 510 and the cap structure 530. It will be appreciated that inhalation of the pathogen may be by one of the above methods or a combination of more of the above methods. It will be appreciated that the term "suction" may be any fluid power or torque, for example to create vortices in the fluid due to changes in the physical configuration of the device. It will be appreciated that the pathogen need not be completely enclosed within the interior portion of the device to be damaged. For example, if only a portion of the pathogen is in the interior portion of the device, the pathogen may also be damaged as a result of operation of the disclosed embodiments.

It is understood that the components of the apparatus 100, 200, 400, 500 may have actions that are pathogen specific and may affect operation. For example, the elastic material 520 may have the property of not contracting when in contact with the normal structure within the body, thereby preventing damage to the structure.

It will be appreciated that the above-described devices 100, 200, 400, 500 may destroy many pathogens during the time the device is located within the body. It will be appreciated that some or all of these devices may be withdrawn from the body under the influence of forces and torques generated by externally located magnetic actuators.

It will be appreciated that the particles may be administered prophylactically to a person who has been exposed to a pathogen or suspected of having been exposed to a pathogen, to reduce the number of pathogens that survive in the body, thereby reducing the risk of subsequent disease caused by the infection.