Continuous processing using plasma

Abstract

To provide a continuous method for producing a product for the prevention and remediation of bacterial contamination, and an apparatus for producing such a product.SOLUTION: An electrode assembly according to the present invention is for exposing an object supported on a moving surface to an electric discharge and includes a) a discharge device capable of generating an electric discharge, and including an electrode having a discharge generation surface capable of generating an electric discharge emanating from an active portion of the surface, the surface being movable to allow generation of an electric discharge from different portions of the surface, b) a barrier closely spaced relative to an inactive region of the electrode, the barrier separating the active portion of the electrode from the inactive portion of the electrode, and c) means for cooling the inactive portion of the electrode.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for producing products having molecules or macromolecules attached thereto. Such macromolecules include bacteriophages. Thus, the products of the methods of the invention are for the prevention and amelioration of bacterial contamination of the products or methods of the invention or materials in contact with the products. [Background technology]

[0002] Bacteriophages ("phages") are viruses that infect and replicate within bacteria. "Lytic" bacteriophages cause the bacterial cell to break open (lyse) and be destroyed after replication of the virion within the bacterium. Once the cell is destroyed, the progeny of the phage can find a new host to infect. Bacteriophages are the most abundant life forms on Earth. They can be found in all environments where bacteria grow. For example, bacteriophages are detected in ground and surface water, soil, food (e.g., sauerkraut, wine), sewage and sludge. They have also been isolated from humans and animals, for example, from feces, urine, saliva, spit, rumen and serum. It is known to impart free bacteriophages to products, for example by spraying. However, it is not known whether such treatments are reliably effective in preventing or treating bacterial contamination.

[0003] Bacteriophages are able to penetrate different organs and tissues, including the central nervous system, and are part of the gut microbiota along with their bacterial host. They are responsible for 10-80% of total bacterial mortality in aquatic ecosystems and are an important factor limiting bacterial populations.

[0004] Bacteriophages can be dispersed in both solid and liquid media. International Patent Application WO03 / 093462 discloses that immobilized bacteriophages can be covalently attached to substrates using chemical methods or electrical discharge, and are unable to diffuse freely, but retain the ability to infect cells, thereby subsequently causing bacterial lysis to release free bacteriophages.

[0005] In WO2007 / 072049 a method was developed for using a pulsed field corona discharge and immersing particles activated by the discharge in a bacteriophage solution. Similarly, in WO2012 / 175749 a bacteriophage solution was combined with activated seeds.

[0006] Therapeutic uses of bacteriophages are known. WO03 / 093462 discloses a method for immobilizing viruses (especially bacteriophages) while retaining their biological activity for use as antibacterial agents. Given that the natural environment of bacteriophages is aqueous, it is widely believed that the stability to dehydration disclosed in WO03 / 093462 tends toward natural stability in aqueous media.

[0007] WO2012 / 175749 describes small particles having attached bacteriophages, which are suitable for combination with food to ameliorate the bacterial contamination thereof as disclosed therein.

[0008] WO2014 / 049008 describes small particles carrying bacteriophages, which are particularly suitable for the treatment or prevention of bacterial infections.

[0009] Wang et al. (2015) [Reference [1] at the end of the specification] showed that low-pressure plasma treatment (a form of electrical discharge treatment) for 1 minute in an oxygen atmosphere enhanced the attachment of bacteriophage to surfaces.

[0010] Such treatment of surfaces allows for stable binding of molecules or macromolecules (including phages) and is called "activation". Surface activation by corona discharge or other plasma-generated electrical methods is well known (e.g., Barton et al. [2]; Canavan et al. [3]; Recek et al. [4]; Kerkeni et al. [5] and others). In industrial practice (e.g., printing), it is well known that such electrical treatments increase the hydrophilicity (wettability) of the surface and thus improve adhesion. This increase in adhesion through increased hydrogen bonding differs from the use of rapid contact between electrically activated surfaces and bacteriophages described in the above patents to achieve covalent binding.

[0011] Furthermore, US 7,250,195 discloses generating a corona discharge and introducing it into a vacuum chamber for depositing biomaterials (including amino acids and proteins but not bacteriophages) onto a substrate.

[0012] WO2014 / 134297 discloses a method for covalently attaching bacteriophage to a surface by forming carboxylic acid residues on the surface of the substrate to which the bacteriophage can be covalently attached.

[0013] In the field, only batch production methods are practical: for example, materials are placed in a shallow activation vessel and subjected to corona activation from above, immediately followed by contact with a solution containing the bacteriophage to be immobilized. This method is more or less acceptable for sheet (flat) materials, where immobilization occurs on one surface, but also makes its use inefficient for filamentous and particulate materials.

[0014] Methods for continuous treatment of articles using corona discharge are known. For example, US2015 / 0373923 discloses a plasma treatment device for treating crops (such as sprouts) to reduce bacterial viability, and US2004 / 0086433 discloses an apparatus with a conveyor for exposing objects to corona discharge. Furthermore, US3,017,339 discloses a method and an apparatus for treating thermoplastic tubes with corona discharge. However, no method has been developed for continuous treatment of articles using corona discharge to attach macromolecules (such as bacteriophages) to the articles.

[0015] Therefore, there is a need for a continuous manufacturing method for producing products with covalently bound bacteriophages. This is especially true for products that contain small particles with bacteriophage attached. Methods commonly used in industry (e.g. standard corona discharge treatment) are not suitable for activating small particles. Unlike films, small particles are susceptible to being dispersed by forces caused by static electricity buildup, and moreover, typically blown air is used to cool the electrodes in these industrial processes, which has no effect on films but can displace small particles and prevent their activation. Summary of the Invention [Problem to be solved by the invention]

[0016] It is an object of the present invention to provide a continuous method for producing a product for the prevention and remediation of bacterial contamination, and an apparatus for producing such a product. [Means for solving the problem]

[0017] Thus, the present invention provides a method for attaching molecules or macromolecules to an object, the method comprising the steps of: placing an object on or near the surface; controlling the electrical potential of the surface relative to its surroundings; activating the object by exposing it to an electrical discharge; and Contacting the object with the molecule or macromolecule to be attached. [Brief description of the drawings]

[0018] [Figure 1] As also described herein, a schematic diagram of an apparatus 100 as described herein is shown in the process of treating microparticles to attach infectious bacteriophage thereto. [Diagram 2] 1 shows an isometric view of an apparatus 200 as described herein for processing microparticles to attach infectious bacteriophage thereto, as also described herein. [Diagram 3] 2 shows a cross-sectional view of an apparatus 200 as described herein for processing microparticles to attach infectious bacteriophage thereto, as also described herein. [Figure 4] 2 shows a side view of an apparatus 200 as described herein for processing microparticles to attach infectious bacteriophage thereto, as also described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The object need not be in direct contact with the surface, but must be in such proximity to the surface that the electrical potential of the surface directly affects and / or defines the electrical potential of the object.

[0020] The electrical potential of a surface, and therefore objects in contact with or in close proximity to the surface, may be controlled by electrically grounding the surface. Thus, the surface may be earthed. Alternatively, the electrical potential of a surface, and therefore objects in contact with or in close proximity to the surface, may be controlled by limiting the charge accumulated by the surface and / or objects in contact with or associated with the surface. This is done by dissipating the charge continuously, or by dissipating the charge when the net charge reaches a predetermined threshold. That is, all or part of the excess negative or positive charge accumulated by the surface may be dissipated by grounding or other means. The charge dissipated may have a potential of up to 10,000 volts / centimeter and may produce 500 millijoules of energy during discharge.

[0021] Control of the electric potential of a surface can be conveniently achieved by performing surface conduction. Thus, to accommodate grounding, the surface or the object or part thereof attached to the surface can be conductive. Preferably, the surface or the object or part thereof to which the surface is attached is partially or completely metallic and therefore inherently conductive.

[0022] The discharge may be a corona discharge. The generation of a corona discharge requires a source of electrical resistance within the device containing the corona source, which may be from the electrode, the surrounding ground / treatment area, or both.

[0023] The corona discharge generating electrode can be ceramic. Ceramic electrodes are advantageous and suitable for generating corona discharges, especially when the processing platform is conductive, i.e., contains metallic elements or conductive materials. Ceramic electrodes also have an advantageously extended service life, since they are resistant to degradation by high voltages.

[0024] The use of ceramic as a resistor around the electrode advantageously distributes the discharge force evenly while still providing effective and reliable processing.

[0025] Alternatively, a metal electrode with a source of electrical resistance attached to the grounded area may be used for applications where the treatment effect spans a larger distance.

[0026] Also, the use of a conveyor belt included in the apparatus or used in the method provides a low electrical resistance, which advantageously helps to keep the effectiveness of the treatment uniform.

[0027] Alternatively, or in addition, the electrical potential of the surface may be controlled by a second electrode in a position that can be used to counter or adjust the electrical potential induced by exposure of the surface and objects placed thereon to the discharge.

[0028] Preferably, this additional electrode is positioned on the opposite side of the object and / or surface from the discharge source.

[0029] In this way, the potential of an object on or in contact with the surface is also controlled by the means for controlling the electric (electrostatic) potential of the surface. This may also be true if the object is in indirect contact with the surface, and its potential may also be controlled in coordination with the potential of the surface.

[0030] The surface is typically a moving surface, thereby allowing continuous attachment of molecules / polymers to the objects. The surface may be a conveyor platform. It is a moving surface suitable for transporting objects along a predetermined path. Preferably, the surface is a conveyor belt. A second additional electrode for controlling the electrostatic potential of the surface and the objects thereon may therefore be placed below the conveyor platform.

[0031] The present invention is therefore particularly suited to continuous processing. Continuous processing is contrasted with batch processing, in which a fixed amount of object or input substrate is processed through a process that has a predefined start and end point. In contrast, in a continuous process, the amount of material or object processed is defined by the amount of material available and the time the process runs. Once the processing process and the flow of inputs and outputs are stable, the product of the process can be produced for an indefinite period of time before the continuous process is stopped.

[0032] Naturally, electrostatic effects are much less significant or detrimental for batch processes because there is much less opportunity for static charge buildup. Also, batch processes can be built around rigid (i.e., non-flexible) surfaces such as metal plates, whereas continuous belt-driven processes require flexible surfaces. Furthermore, because electrical activation is only used intermittently, the opportunity for built-up charge to dissipate naturally is significantly greater.

[0033] Heretofore, treatment of articles with electrical discharges has been performed on a wide variety of substrate materials and objects without adversely affecting the positioning of the object due to charge overload. Generally, the size and / or mass of the treated object has been sufficient to render any forces due to the presence or accumulation of charge insignificant.

[0034] It was therefore unexpected that the treatment of particles using electrical discharges would be substantially prevented by the particles becoming charged during the treatment process, with movement of all or part of the population of particles being treated making the treatment less reliable and / or less effective than expected and / or required.

[0035] Therefore, the inventors have developed the method and apparatus of the present invention, which allows for the control of the electric potential, providing the advantage of eliminating, reducing or otherwise controlling electrostatic effects that may act on the object being treated. Small objects are disproportionately affected by static effects, in that electrostatic charges may cause small particles to repel or attract each other, leading to uncontrolled dispersion or uncontrolled agglomeration. In either case, efficient processing of the particles becomes difficult or impossible. Particles of excessively high charge are repelled by the discharge to such an extent that they do not pass through the corona and are not activated. Furthermore, the accumulation of static electricity may cause small particles to disperse in a random and unpredictable manner, which makes them unable to be efficiently activated by the discharge. Such effects are particularly pronounced when the particles are formed in a monolayer, and are therefore disadvantageous.

[0036] Furthermore, these electrostatic effects on the objects being treated can be caused or exacerbated by exposure to external electrical discharges.

[0037] The object provides a substrate for the attachment of molecules or macromolecules thereto, and thus the terms object and substrate are used interchangeably herein.

[0038] The term "substrate" is understood to mean any solid phase material on which molecules or macromolecules can be immobilized after exposing the substrate to an appropriate electrical discharge. The substrate can take many forms, such as nylon and any other polymer with amino or carboxyl surface groups, cellulose or other hydroxyl-containing polymers, polystyrene or other similar polymers, magnetic particles, various plastics or microbeads containing biological materials. The substrate can also be made from materials commonly used in therapy / medicine, such as nylon threads for use in surgery; plastics, lint or gauze materials for dressing open wounds; microbeads (which are ingestible); adhesives (e.g. cyanoacrylate); and / or biological materials (e.g. collagen or hyaluronic acid). More preferably, the material can be food or feed particles containing proteins and bulk materials (e.g. cellulose or other plant-derived polymers).

[0039] The term "activated / activating / activation" according to the present invention is understood to mean activation of the substrate by reacting it with various chemical groups (leaving a surface chemistry available for binding to bacteriophage head or capsid groups). Activation of the substrate is achieved by electrical discharge (preferably corona discharge). However, other forms of electrical discharge may be used. In particular activation of the substrate may be achieved by applying a pulsed corona discharge and / or an electron beam. Contact between the molecule or polymer and the activated substrate leads to the formation of a covalent bond between the molecule or polymer and the substrate. The use of the term "attached" in the context of the present invention therefore means a covalent bond.

[0040] The substrate may be a particle. The particle may have a size of 2 mm or less in diameter, preferably 1 mm or less in diameter, most preferably in the range of 1 to 1000 μm. The particle may be substantially spherical.

[0041] Suitably, the particles may be food pellets. The food pellets are suitable for human and / or animal consumption. Preferably, the food pellets are suitable for use as animal feed. The pellets may preferably range from 1 mm to 20 mm in height, measured from the surface on which they are placed or supported. The pellets may be substantially spherical, cylindrical, or spherocylindrical.

[0042] The object may also be a seed (e.g., a plant seed). Seeds may be advantageously treated according to the present invention due to the effect of static electricity on the handling of small objects such as plant seeds. Seeds suitable for treatment according to the present invention may be 10 mm or less in diameter, preferably in the range of 0.2 to 5 mm.

[0043] The molecule or macromolecule may be a biomolecule or a biological entity. The biomolecule may be an antibody, a cytokine, or other signaling molecule. Alternatively, or in addition, the molecule or macromolecule may be a biological entity such as a multimeric protein or an antibody, or a virus. Preferably, the macromolecule is a virus, and most preferably, the macromolecule is a bacteriophage.

[0044] The term "bacteriophage" according to the present invention refers to a bacteriophage that infects a specific strain of bacteria. It will be understood by those skilled in the art that a bacteriophage can recognize and infect a specific strain of bacteria. Thus, the substrate may be a material that can be advantageously activated to allow headgroup specific binding of complex bacteriophages. The bacteriophage is immobilized via a covalent bond formed between the bacteriophage coat protein and the substrate. More preferably, the bacteriophage is immobilized on the substrate via their headgroup or nucleocapsid by activating the substrate prior to addition and coupling of the bacteriophage.

[0045] Thus, the bacteriophage immobilized on the substrate according to the invention may be utilized to combat strain-specific bacterial infections as a "bactericide" by inducing selective killing of bacteria via cell lysis by inhibiting the growth of the bacterial cells. The bacteriophage immobilized on the substrate may also be used as an antibacterial / disinfectant to "kill" bacterially contaminated materials. Thus, preferably, the bacteriophage retains infectivity upon immobilization.

[0046] The surface may also include a cavity or indentation for accommodating the particle. The mouth of the cavity or indentation preferably faces the source of the electrical discharge when the particle therein is activated by the electrical discharge. Preferably, the indentation or cavity is sized to accommodate a single particle.

[0047] Preferably, the particles accommodated by the cavity or indentation are 1 cm in diameter or larger. The force required to process larger particles is significantly higher than for smaller particles because the force requirements follow an inverse square law for a linear increase in size.

[0048] Thus, the surface may be made with an indentation in which the particle fits. A portion of the particle protrudes from the cavity or indentation above the surface of the surface. Thus, the linear range that the corona discharge must cover to effectively treat the protruding portion of the particle may be significantly lower. In this way, a significant and effective portion of the particle can be activated without the need to treat the entire particle. Thus, a lower power discharge source can be used. Such a lower power discharge source is advantageously cheaper to obtain, implement and maintain.

[0049] The present invention also provides an apparatus for treating an object by attaching molecules or macromolecules, comprising: a surface for supporting the particles to be treated; means for controlling the electric potential of said surface relative to its surroundings; A discharge device capable of producing an electrical discharge.

[0050] The invention also provides the use of the device of the invention for attaching molecules or macromolecules to particles.

[0051] The present invention also provides an electrode assembly comprising: The device comprises a discharge device capable of generating a discharge, and further comprises an electrode having a discharge generation surface capable of generating a discharge emanating from an active portion of the surface, wherein the surface is movable to allow generation of a discharge from different portions of the surface.

[0052] The discharge can be generated continuously while the discharge generating surface is moving.

[0053] The advantage of a movable electrode surface is that the heat energy that must be dissipated during operation of the electrode is generated in a specific part of the electrode, and this part can be changed during use to more evenly distribute the heat energy generated during operation. In this way, hot spots on the electrode are avoided and the operating life of the electrode is increased with improved reliability.

[0054] The movable electrode is rotatable, and preferably the electrode is cylindrical. Such an arrangement is convenient in that only one direction of movement is required to produce the benefits of moving the electrode during continuous use.

[0055] The electrode assembly may further comprise means for cooling the inactive portion of the electrode. Preferably the cooling means is air cooling, most preferably the cooling means is forced air cooling.

[0056] The electrode assembly includes a barrier closely spaced relative to the inactive region of the electrode, the barrier separating the active portion of the electrode from the inactive portion of the electrode. This configuration has the advantage of separating the "active" side of the electrode, where objects are activated, from the "inactive" side of the electrode, where cooling may occur. In this way, the two temperature environments are separated, preventing the cooling mechanism from affecting the processing mechanism on the other side of the barrier.

[0057] The barrier may be made from rubber or plastic, but preferably the barrier is made from a silicone material.

[0058] The barrier may be in contact with the surface of the electrode or closely spaced apart from the electrode surface, preferably located 10 to 1000 μm from the electrode surface.

[0059] Such materials and configurations have the advantage of allowing the barrier to act as a scraper to remove particles or other material that has adhered to the surface of the electrode, thus allowing the electrode to operate continuously for longer periods of time.

[0060] The present invention also provides the use of the electrode assembly of the present invention for attaching molecules or macromolecules to a substrate.

[0061] The present invention is illustrated in the following specific embodiments with reference to the accompanying drawings. EXAMPLES

[0062] Example 1 An apparatus 100 for treating microparticles to attach infectious bacteriophage thereto is shown in FIG.

[0063] The following components of the device are shown in Figure 1: 101 - a hopper containing fine particles to be deposited on the belt; 102 - a moving belt, which is either manufactured of a conductive material or made conductive by the addition of a second electrode, thereby grounding the particles, thus greatly reducing or eliminating the problem of static electricity build-up; 103-The barrier across the belt ensures that only one (monolayer) of particles enters the corona region; 104 - A rotating ceramic electrode, which generates a corona to activate the material. The rotating electrode allows cooling of the top surface through the flow of air flow; 105-Air flows over the top of the electrode to allow cooling; 106- A silicone polymer blade separates the feed from the air stream and skims any adhering particles off the electrode surface; 107- Barrier to prevent liquids from contacting the corona; 108—A device for spraying a phage suspension onto the activated feed, which has a reservoir for the phage suspension; 109-Hopper for collecting phage immobilization feed.

[0064] Thus, during operation, the moving (conveyor) belt 102 has particulates deposited on it from the hopper 101. The particles are 2 mm or smaller and electrostatic effects can cause them to move as they spread or disperse in an uncontrolled manner. The particles deposited on the belt travel under the barrier 103 and travel laterally across the belt 102, forming agglomerates of particles that flatten into a single layer on the belt 102 in preparation for bulk processing of the particles.

[0065] The conveyor surface is made of a conductive material or its potential is manipulated using a second electrode. This serves to earth or ground the particles, eliminating static electricity and thus eliminating the movement of particles on the conveyor due to static electricity. Such an effect is particularly noticeable when the particles are formed in a single layer.

[0066] The monolayer of particles moving on the conveyor then passes through a corona discharge 110, causing activation of the surfaces of the particles. The activation produces reactive free radicals on the surfaces of the particles.

[0067] The electrode that generates the corona discharge 104 is preferably ceramic because the conveyor belt is electrically conductive, making ceramic electrodes preferred for compatibility. The ceramic electrode 104 is also cylindrical and rotates while generating the corona discharge 110. The lowest portion of the curved surface of the cylindrical electrode 104 is oriented transverse to the direction of conveyor belt movement and faces the particles traveling on the conveyor belt 102. The electrode generates the corona discharge from this lowest portion of its surface facing the conveyor belt.

[0068] The resonant rotation of the cylindrical electrode 104 while creating a corona discharge causes previously inactive portions of the electrode to come into use as the electrode surface rotates, constantly changing the active portion of the electrode. The creation of a corona discharge generates heat, causing the temperature of the active portion of the electrode to rise. The rotation of the electrode allows the previously active portion of the electrode 104 to rotate into a cooling area 105 where air flows over the inactive upper portion of the electrode 104, cooling it before that portion of the electrode becomes active once again.

[0069] The silicone polymer blades 106 are also positioned in close parallel separation along the length of the curved cylindrical surface of the ceramic electrode. The presence of these silicone polymer blades 106 allows for the separation of the atmosphere on the "active" side of the electrode from the atmosphere on the "inactive" side of the electrode. In this way, the effectiveness of the cooling system where air passes over the "inactive" side of the electrode is improved, and the cooling air passing over the "inactive" side does not blow or affect the fragile monolayer of particulates that has formed on the conveyor belt facing the "active" side of the electrode. The placement of the blades 106 in close parallel separation with these curved surfaces of the electrode 104 also allows particles that may have attached to the surface of the electrode due to static charge or other reasons to be scooped off the rotating electrode during the treatment process.

[0070] The activated particles on the conveyor then pass through openings in screen 107 into a spraying area where a suspension of bacteriophage in carrier liquid is sprayed from reservoir 108 onto the activated particles. Spraying the activated particles with bacteriophage causes the surface of the bacteriophage to react with free radicals present on the surface of the activated particles, covalently binding the bacteriophage to the particle. Bacteriophage attached in this way are able to retain their infectivity and are significantly less susceptible to dehydration, chemical activation or phagocytosis. The suspension contains 1×10 4 ~1×10 12 bacteriophage. The suspension is applied by passing the suspension through a spray nozzle to form a spray made up of droplets of average diameter Y μm. A pump is used to apply the suspension at a flow rate of Y ml per second. The spray nozzle is positioned Y mm from the activated phage while the bacteriophage-containing spray is being applied.

[0071] Once the bacteriophage are covalently attached to the particles, the conveyor delivers the particles to a storage hopper 109 .

[0072] Example 2 An apparatus 200 for treating microparticles to attach infectious bacteriophage thereto is shown in FIGS.

[0073] The following components of the device are shown in Figures 2 and 3: 202—A moving belt, the potential of which and that of items placed on it is controlled via a second / opposite electrode 210. This grounds the particles, thus greatly reducing or eliminating the problem of static build-up. 204 - Rotating ceramic electrode, which generates a corona to activate the material. The rotating electrode allows cooling of the top surface through the flow of air flow; 205 - Cooling pipes, supplying / flowing air over the top of the electrode to allow cooling; 206- A silicone polymer blade separates the feed from the air stream and skims any adhering particles off the electrode surface; 207- Barriers to prevent liquids from contacting the corona; 210-counter electrode; and 212-High voltage (HV) cable.

[0074] Thus, during operation, the moving (conveyor) belt 202 has particulates deposited thereon from a hopper or other container (not shown). The particles are of a size such that electrostatic effects can cause them to move upon diffusion or disperse in an uncontrolled manner. The particles deposited on the belt travel under a barrier (not shown) and travel laterally across the belt 202, forming agglomerates of particles that are flattened into a single layer on the belt 202 in preparation for bulk processing of the particles.

[0075] The potential of the conveyor surface is manipulated with a second electrode acting as a counter electrode. This helps to control the electrostatic charge generated by the particles and to control or prevent the movement of particulates on the conveyor due to static electricity. Such effects are particularly noticeable when the particles are formed in a monolayer.

[0076] The monolayer of particles traveling on the conveyor then passes through a corona discharge, which causes activation of the surface of the particles, which generates reactive free radicals on the surface of the particles.

[0077] The electrode that generates the corona discharge 204 is ceramic. Also, the ceramic electrode 204 is cylindrical and rotates while generating the corona discharge. The lowest part of the curved surface of the cylindrical electrode 204 is oriented transversely to the direction of movement of the conveyor belt and faces the particles traveling on the conveyor belt 202. The electrode generates the corona discharge from this lowest part of its surface facing the conveyor belt. The electrical energy to generate the corona discharge is supplied via a high voltage (HV) cable 212. The HV cable is kept at a safe distance of 60 mm from other conductive materials.

[0078] The resonant rotation of the cylindrical electrode 204 while creating a corona discharge causes previously inactive portions of the electrode to come into use as the electrode surface rotates, constantly changing the active portion of the electrode. The creation of a corona discharge generates heat, causing the temperature of the active portion of the electrode to rise. The rotation of the electrode allows the previously active portion of the electrode 204 to rotate into the vicinity of a cooling pipe 205, where air flows over the inactive upper portion of the electrode 204, cooling it before it becomes active again.

[0079] Silicone polymer blades 206 are also positioned in close parallel separation along the length of the curved cylindrical surface of the ceramic electrode. The presence of these silicone polymer blades 206 allows the separation of the atmosphere on the "active" side of the electrode from the atmosphere on the "inactive" side of the electrode. In this way, the effectiveness of the cooling system where air passes over the "inactive" side of the electrode is improved, and the cooling air passing over the "inactive" side does not blow or affect the fragile monolayer of particulates that form on the conveyor belt facing the "active" side of the electrode. The placement of the blades 206 in close parallel separation with these curved surfaces of the electrode 204 also allows particles that may have attached to the surface of the electrode due to static charge or other reasons to be scooped off the rotating electrode during the treatment process.

[0080] The activated particles on the conveyor then pass through openings in a screen (not shown) into a spraying area where a suspension of bacteriophage in a carrier liquid is sprayed from a reservoir (not shown) onto the activated particles. By spraying the bacteriophage onto the activated particles, the surface of the bacteriophage reacts with free radicals present on the surface of the activated particles, covalently attaching the bacteriophage to the particle. Bacteriophage attached in this way are able to retain their infectivity and are significantly less susceptible to dehydration, chemical activation or phagocytosis. The suspension contains 1 x 10 4 ~1×10 12 The suspension comprises the bacteriophage. The suspension is applied by passing the suspension through a spray nozzle to form a spray made up of droplets.

[0081] Once the bacteriophage are covalently attached to the particles, the conveyor delivers the particles to a storage hopper (not shown).

[0082] The invention thus provides a method and apparatus for treating a substrate to adhere a substance thereto, the use of the apparatus and products provided by applying the method of the invention using said apparatus.

[0083] (References) [1]C. Wang,D. Sauvageau,A. Elias Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces. ACS Appl. Mater. Interfaces 2016,8,1128-1138 [2]Barton,D.;Short,RD;Fraser,S.;Bradley,JW The Effect of Ion Energy upon Plasma Polymerization Deposition Rate for Acrylic Acid. Chem. Commun.(Cambridge,U.K)2003,7,348-349. [3] Canavan, HE; ​​Cheng, X.; Graham, DJ; Ratner, BD; Castner, DG A Plasma-Deposited Surface for Cell Sheet Engineer-ing:Advantages over Mechanical Dissociation of Cells. Plasma Processes Polym. 2006,3,516-523. [4]Recek,N.;Mozetic,M.;Jaganjac,M.;Milkovic,L.;Zarkovic,N.;Vesel,A. Adsorption of Proteins and Cell Adhesion to Plasma Treated Polymer Substrates. Int. J. Polym. Mater. 2014,63,685-691. [5]Kerkeni,A.;Behary,N.;Dhulster,P.;Chihib,N.;Perwuelz,A. Study on the Effect of Plasma Treatment of Woven Polyester Fabrics with Respect to Nisin Adsorption and Antibacterial Activity. J. Appl. Polym. Sci. 2013,129,866-873.

Claims

1. 1. An electrode assembly for exposing an object supported on a moving surface to an electrical discharge, the electrode assembly comprising: a) a discharge device capable of generating an electric discharge, the device further comprising an electrode having a discharge generation surface capable of generating an electric discharge emanating from an active portion of the surface, the surface being movable to allow generation of an electric discharge from different portions of the surface; b) a barrier closely spaced relative to the inactive region of the electrode, separating the active portion of the electrode from the inactive portion of the electrode; c) Means for cooling said inactive portion of said electrode.

2. The electrode assembly of claim 1 , wherein the discharge occurs continuously while the discharge generating surface moves.

3. 3. The electrode assembly according to claim 1 or 2, wherein the discharge is a corona discharge.

4. 4. An electrode assembly according to any of claims 1 to 3, wherein the means for cooling the inactive portion of the electrode is air cooling, preferably forced air cooling.

5. 5. The electrode assembly of claim 1, wherein the barrier is made of rubber or plastic.

6. The electrode assembly of claim 5 , wherein the barrier is made of a silicone material.

7. 7. The electrode assembly according to claim 1, wherein the corona discharge generating electrode is ceramic.

8. 7. The electrode assembly according to claim 1, wherein the corona discharge generating electrode is metallic.

9. 9. A method of exposing an object to an electric discharge, comprising the step of exposing the object to an electric discharge generated by an electrode assembly according to any one of claims 1 to 8.

10. 10. A method for attaching molecules or macromolecules to an object according to claim 9, comprising the steps of: a) activating the object by exposing it to an electrical discharge generated by the electrode assembly according to any one of claims 1 to 8; and b) contacting said object with said molecule or macromolecule to be attached;

11. 11. The method of claim 10 for attaching a molecule or macromolecule to an object, wherein the molecule or macromolecule is a bacteriophage.

12. 9. Apparatus for exposing an object to an electric discharge, comprising an electrode assembly according to any one of claims 1 to 8.

13. Use of an electrode assembly according to any one of claims 1 to 8 for exposing an object to an electric discharge.

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